Some backstory, my sister (25) lives in a different state, and when she comes to visit, her and her husband drive several hot beverages, requiring mugs (I swear this isn't a shitpost). I have about 4 mugs that I cherish from a family vacation a few years back, and they are no longer made (aka not replaceable) and she uses them when she's here, and doesn't rinse them, and leaves horrid rings in them. So far I have lost one mug to nasty rings that ruined to glaze, so it's unusable. I don't want her to use them anymore. My mother doesn't want me to bring it up, because she thinks I'll disrupt the family peace. Also, I have told her numerous times to please rinse them, and she doesn't. So, WIBTA is I told her she isn't to use them anymore?