By the way, doctor: Are there any good DEET-free repellents?
Q. DEET makes a mess of my fly fishing gear. I've heard there are some new mosquito repellents that don't contain DEET. Are they any good?
A. N,N-diethyl-m-toluamide — DEET for short — is the active ingredient in many major brands of mosquito repellent, such as OFF! DEET is a strong chemical that can damage plastic (including artificial fingernails), rayon, spandex, leather, and painted or varnished surfaces. People who fish must be careful to wash DEET off their hands because it can dissolve fishing line, wader material, and related gear.