I use a damp cloth with a little soap in it. Not soaking because you don't want water getting into the wood, but wet enough to get the shell going toward clean. I use a number different things, and many are unorthodox and scare hell out of most people, but the truth is, I have yet to damage a shell by cleaning it.
I have a nifty little tool called a Sonic Scrubber Pro Detailer. I think I paid like 10 bucks for it somewhere. Looks like a toothbrush. Anyway, I sometimes put the large, soft head on it and spray 409 if the shell/wrap has a lot of nicotine and sticky residue from adult beverages, and just scrub away. Maybe I should post a video of this sequence to show how well it works. It sounds like I am a nut, but I am very meticulous, and I love my drums and my craft, so I take it very seriously. My craft is restoration of many things, as my Mom was an antique dealer and I grew up learning to clean and polish, tear down, put back, repair, replace and repaint all manner of stuff. I even use sandpaper to recut bearing edges. Poly and glitter makes old, junky MIJ and MIT drums (Made In Japan/Made In Twiwan) come back to life and sound great, and then I give them to deserving children. flower
Anyway, Stuff cleans drums, use it, I am an endorcer of fine, clean drums and hardware and the Stuff that cleans them, and I heartily invite you to try it out, you'll like it!Excited