Magic eraser works very well. If you have real stubborn gunk, use a magnifying glass(jewel loupe) or microscope and a small piece of the ME and gently work with the tip of the stylus to loosen the stuff. on very rare occasions, i have tried the "chemical" solution to soften but ME usually does the trick. Put the cartridge on the Microscope to really see if you have an issue. Kinda changes your perspective when the stylus looks like a chisel up close. Easy to see what you are dealing with and if you have steady hands really helps you clean it
