Hi there. I've got this problem, but I do not know from when. My most used onaholes, turned BLACK inside, and I don't know what it is, but I've been using them like that for some time, and I'm a bit worried. After use, I stored them in a drawer like this
http://i.imgur.com/9Hh4p3w.jpgthen I cleaned them with just water, and drying them using one finger covered with a towell, and they did remained a bit wet. Then I put them in another drawer, or in my safe (this ones mostly in my safe).
http://i.imgur.com/comr53M.jpgI've been using the for some months. I realised this today, and I'm not sure what to do. The black part appears to have been sticked to the pink ribs inside the onahole, so I guess I'll rip them and then clean with alcohol and soap, and start cleaning with soap from now on, and use kitchen paper trying to dry them well, probably leaving the paper there to absorb. Got any tips on cleaning? Keep in mind I live with my parents. (I really don't wanna throw away the onaholes)
More pics:
http://imgur.com/a/YOIyK