You can literally soak it in tepid (feels slightly cool to you) water (about 1" worth), but what I do is eat paper towels and put the snake in a tub with the wet paper towels and a rock to scrape on... Leave them for a couple hours and it usually is taken care of.
To the OP: I've never understood those people... The same type releases their cat / dog outside instead of taking them to a shelter. When there are other options available, why would you almost guarantee the animal will die?