Turn off the power that controls your chandelier. Wait to do any work until the light bulbs on your fixture feel cool to the touch. You do not need to disconnect the electricity, but you may as an extra precaution since this step involves disassembling the fixture. Disconnect power from the room only if you are confident in operating your home’s circuit breaker or have assistance from a knowledgeable electrician. You should not need to adjust any electric wiring in this process. While you’re waiting for the bulbs to cool, prepare your workspace. Place a thick blanket on the floor under your chandelier, as well as across a nearby table or whatever surface you plan to place chandelier parts on. Set up a stepladder or taller ladder securely under the chandelier.  A heavy, thick blanket or cloth is essential for underneath your workspace, as it will soften the landing and prevent breakage in the case of pieces falling during disassembly. If you don’t have one, fold over another cloth several times to make it thicker.  Make sure your ladder is at a height that is comfortable to reach all parts of the chandelier.  Inspect your chandelier and take photos from several different angles and distances so you will remember how to reassemble it later. Carefully remove each crystal from the chandelier and place it on a nearby surface that is stable and covered with a blanket or thick cloth.  You may disassemble other larger parts of the chandelier or take down the whole fixture entirely if it is possible to do so safely and without affecting wiring or the fragile parts of the chandelier. You may need needle-nose pliers or a similar tool to unfasten each crystal piece, depending on your chandelier. You can also use them to reshape the crystal fasteners during reassembly to strengthen them. Fill a sink with warm water and a small amount of mild dish soap. Line the sink with a cloth or towel to provide padding. Place crystals into the padded sink and rub each one separately with your fingers in the soapy water before rinsing and placing on a soft, clean towel.  Take care to prevent crystals from hitting against each other or against hard surfaces of the sink to avoid cracking or chipping. There is no need to use a sponge or brush to clean crystals with the soapy water, and in fact this could end up scratching them. Dry the crystals with a soft, absorbent cloth immediately after rinsing. This is essential to preventing dried water spots from forming. If you need to, clean the frame, bulbs, and any other parts of the chandelier with a soft, dry cloth. Replace bulbs if they are dim, broken, or discolored.  You may be able to use the same soapy water or other cleaner on the frame or other parts of the chandelier. Check first about the variety of metal or other material they’re made out of to find the right cleaner for it. Be sure to thoroughly dry any moisture that has remained in light bulb sockets or other areas of electrical connection. Dry as best you can with a cloth, then leave parts out to dry further for several hours before assembly if necessary. Work from your photos or memory to replace all parts, bulbs, and crystals to where they belong in the fixture. While assembling, work from the top down and from inside to out to put all the pieces back together easily.
Turn off the light to let the bulbs cool. Prepare the area. Disassemble the chandelier carefully. Clean the crystals carefully. Clean the frame and other parts. Reassemble the chandelier.