I was reminded of a handy tip a short while ago...
An acquaintance of mine was working with polyurethane a couple of days ago, dropped it and splashed everywhere, including on their skin. Pretty tough to remove, as you can expect!
Vegetable oil or peanut butter is effective at removing polyurethane residue from your skin - simply rub either into your skin well, and wash off with liquid dish soap and rinse well.
The same procedure can be applied to dogs and cats. Typically the polyurethane contamination occurs when curious pet wander through a freshly urethaned floor (which is usually done perfectly, right?), and their paws are just sticky with the mess. Be sure to rinse well and inspect all areas of the body, as the hydrocarbons in the poly can cause severe respiatory dysfunction and even death.
As with all chemicals, there is a serious risk of poisoning when pets have had contact. Get in touch immediately with the ASPCA's Emergency Veterinary Hotline: (888)426-4435