since most people don't know this when they start waxing their own skis, lemme tell you one of the most important skis.
after you iron the wax on, you want to scrape it ALL off. you don't want any wax left on the ski.
the way it works is the way is absorbed into pores in the base of the ski. it's not supposed to be gunked on the bottom.
and for the rest listen to the other guy.