( CNN ) -- Destructive graffiti wars are being waged by anonymous vandals , deliberately defacing many of the meticulously painted murals that vividly illustrate San Francisco 's streets . The attacks have sparked calls by outraged professional artists and their supporters demanding everything from public humiliation to experimental collaboration with the hostile graffiti `` taggers '' to avoid violence and more lost art . If you 're going to San Francisco , keep in mind that the outdoor murals you see are ephemeral , so appreciate them -- and take lots of photos -- before they disappear . Countless gorgeous , larger-than-life murals illustrate this city 's weathered exteriors , bestowing visual intrigue to homes , shops , parking lots , recreational facilities , derelict buildings and alleys . Artistic themes include anarchy , surrealism , science fiction , eroticism and other fantasies and realities . Some gigantic paintings include political slogans or poetry for the public to ponder . Now , however , a rolling population of taggers has been wreaking havoc on many of the best murals , by hurriedly spray-painting initials , names , words , acronyms and other lettering across the majestic urban displays . Gang intimidation at work . Some victimized artists worry that the taggers may include criminal gangs marking their neighborhoods , making it unwise to confront them or remove their destructive scrawls . `` There is always that possibility of violence , if you approach someone tagging a mural , '' said Carlos Daniel Perez-Boza , 26 , who teaches art at San Francisco 's Cultural Arts Division of the Recreation and Parks . `` Some taggers come in large numbers , some are gang related . Their intention is to mess things up and possibly look for a fight , '' he said in an interview . `` I can only hope taggers would appreciate the street arts , and truly see what are the possibilities that we are building , for artists to showcase their talents in public space , '' said Perez-Boza , who is also a muralist , painter , street and studio artist . Mission District art targeted . Clarion Alley , the Mission District neighborhood 's prestigious , free , open-air gallery , is n't immune from desecration . Since 1992 , Clarion Alley 's urban lane has allowed artists to voluntarily adorn its outdoor walls , fences , residences , gutters and every other available space with fanciful and often profound murals . The public alley runs parallel between 17th and 18th streets , linking Mission and Valencia streets -- you can visit anytime day or night for free . Prominent artist Mats Stromberg completed his 12-foot-tall , 15-foot-wide , ant-infested `` Giant Selfie '' Clarion Alley mural in 2013 . His mural portrays a man 's huge turquoise head -- resembling himself -- laying on the ground , `` with two factions of ants battling it out in front of his very eyes , representing the sort of narcissism associated with all the latest social media gadgets , as well as the individual 's helplessness in the face of conflicts either nearby or globally , '' he said in an interview . Stromberg was n't amused when his masterpiece was defaced in July . Big , bold blobs of silver-colored letters , outlined in red -- spelling the name `` Blake '' -- suddenly smothered much of the mural . Asked what punishment anti-mural taggers should suffer , Stromberg suggested perhaps the person should be `` tarred and feathered , and tied to the defaced wall for a few days and nights ? Spray-paint their faces ? '' Compromising with taggers ? Stromberg , whose signature `` Mats ! ? '' includes double punctuation , has seen his art attacked by other taggers in the past . His previous response was to painstakingly paint over the graffiti , and restore his mural . This time , however , Stromberg painted fresh chaotic designs over parts of the silvery letters , rendering `` Blake '' unrecognizable under blossoming , newly evolved weird images . `` My response this time is to collaborate with my tagger , and not return the piece to its original state , but see what happens , '' said Stromberg , 50 , while laboring to repair his mural . `` The tags inspire new visual vocabularies I would not have thought to paint , had the piece not been tagged . '' Tagger response : `` Its war '' In August , `` Blake '' returned with a vengeance to Clarion Alley and ominously wrote in black letters across the repaired mural : `` THIS ISNT ART . ITS WAR . BLAKE . '' `` I wish you could get ahold of Blake , my tagger-collaborator , but I 've no idea who , where , what , he is , '' Stromberg lamented after the fresh assault . Stromberg 's Facebook friends analyzed the tagger 's motive . `` You could think of it in terms of mental illness . It 's Tourette 's -- but they have to write their name over and over maybe , '' posted one colleague . `` He is expressing some sort of superiority -- read : 'internalized inferiority ' -- over a real artist . I was just marveling at the tags on the toilet seat at a local establishment . How low do you have to be , to want to tag that ? '' someone else wrote . `` I really just do n't get why he has chosen to target Mats Stromberg of all people . A legendary , grimy , old school Mission dude , underground pioneer , '' another dismayed artist wrote . `` This same stuff has happened to mine as well . It 's a bummer , but it is good to keep in mind that anything we put out there into the public is ephemeral , meaning it could last a long time or no time , '' that artist said . `` Stick a nanny cam on there , get a mug shot , and then paint the dude 's face on there , wearing a T-shirt that says ' I 'm with stupid ' and an arrow pointing the guy 's head , '' suggested another post . Attack on establishment art . `` I 'm guessing they see a legitimate commissioned or permitted works of art , as being part of the establishment , '' said Stromberg . He was referring to the alley 's envious status of enshrining some of San Francisco 's best art , organized by the volunteer artists ' collective Clarion Alley Mural Project ( CAMP ) . `` Sadly , CAMP has helped to contribute to the extreme gentrification of the Mission District over these past two decades , '' wrote artist Megan Wilson , a CAMP `` core organizer '' who defends the alley 's roots . `` What started as a neighborhood-based project committed to diversity and inclusion , is now a magnet for lots of folks hoping to profit off of the image that CAMP has created -- from the developers and real estate agents who use CAMP as a selling point for the 'cool , hip Mission experience , ' to those who use the space for fashion shoots , to corporations hoping to include the 'gritty urban street art ' image to sell their products , to any number of paid tours by folks unrelated to CAMP , spreading misinformation about the project , artists and murals , '' she wrote on her website . No control over taggers . Many of San Francisco 's large murals are the result of serious negotiations between artists and wall owners -- including shopkeepers , residents or city officials -- to ensure the painting remains visible and not erased for violating private property . But no one can control malicious taggers . `` I believe taggers will always state their voice , '' said Perez-Boza . `` Whether it 's tagging a white wall , a mural , local mom and pop , venues , billboards , public transit or corporate buildings . '' People attack murals because `` they knew the artist , and maybe that artist they knew 'sold out . ' `` Or they at one point were in the same crew , and now they are in different crews . `` Or jealousy and envy . Or they just do n't care . `` Or they can be sending gang messages . `` I do n't know what the punishment should be , if someone intentionally spray-painted over a mural . `` It 's not like the law is involved , unless you 're tagging a McDonald 's ad , '' Perez-Boza said , laughing . `` I had someone tag one of my work-in-progress murals . `` The silly part about this was how they displayed it . `` My wall was about 15 feet high , 20 feet wide . Their mark was no bigger then six inches . '' You can see some of San Francisco 's best murals and other art at websites for the Clarion Alley Mural Project ; Carlos Daniel Perez-Boza ; Mats Stromberg ; SF Mural Arts . Richard S. Ehrlich is a freelance writer from San Francisco . He 's reported for international media from Asia since 1978 , based in Hong Kong , New Delhi and now Bangkok .
Authorized murals and street art routinely being defaced by vandals in San Francisco . Some of best murals in historic Mission District have been ruined . `` Its war '' declared one tagger after an artist attempted to paint over his tag . `` There is always that possibility of violence if you approach someone tagging a mural , '' says local art instructor .