I get some residue when the bases aren't waxed enough. Try stipping the bases and cleaning them very well. Hotwax your skis and keep them waxed to keep that from happening again. Also - never leave the skins on your skis for a long period of time unless you are climbing a skin track. Take them off when you are done. I also do not put skins on at home before heading out to the hills to ski. Same thing can happen again.
Like it or not, all of us are the result of a sexual act.