If you accidentally come across a slug's trail or handle a slug in the garden, your first instinct is likely to run for water so you can wash off that disgusting mucus. Resist this urge. Slugs use their mucus to help prevent dehydration. As such, slug mucus absorbs water -- meaning the mess on your hands will get worse if you try to rinse it off. A little patience will reward you with easy slime removal, although it is admittedly difficult to be patient when you are covered in ick.
Sliding Out of Slime
If you've been slimed, wait a few minutes for the mucus to dry. Then rub your hands together briskly to roll the dried mucus off. Once the mucus is gone you can wash your hands with soap and water. If you're having trouble getting the dried slime to rub off, try using a dry powdered borax hand soap or rubbing a paper towel between your hands. If slime gets on your clothing, treat the area with white vinegar before washing.