DEET dissolves helmets

[PeteJack]

Climbing up to Sequoya a cloud of flies gathered round my head so I sprayed Jungle Juice all over my head and neck including of course my helmet. The stuff worked. It kept the flies off. When I got to the campsite I noticed black sticky stuff on the collar of my jacket like dirty bike chain oil as if I'd tossed my jacket over my bike and the collar had rubbed on the chain. Then I saw the sticky stuff was on my hand and coming from my helmet. The DEET was dissolving my helmet into black sticky goo. One of my co-riders had done the same as me with a different repellant containing DEET and was having the same problem. So don't spray DEET on your helmet.

I washed the stuff off with water and the styrofoam looked like it had acne; REI was good enough to exchange the helmet which was a relief it was only about six months old

[Kittery Rider]

yep melted plenty of sunglasses that way too

[John Nelson]

I would never use a spray DEET. You just cannot adequately control where it goes. I always use lotion DEET, and I prefer to do it after removing clothing that might potentially be damaged.

Reportedly, DEET damages plastics, acetate, rayon, Spandex, synthetic fabrics (other than nylon), furniture finishes, leather, watch crystals, painted or varnished surfaces, plastic glass frames and goggles, and car finishes and interiors. It will not damage nylon, cotton, or wool fabrics.

[Mark Manley]

I have had Deet dissolve plastic, it does make you wonder what it does to your skin.

[mcparsons]

I can say with some confidence that it does not dissolve your skin.   

[Bicycle Rider]

Neither does acetone or methylene chloride, but I wouldn't spread either of them on my skin either!

[Westinghouse]

I have 40% DEET. It sure repels insects, and I would use it sparingly. It dissolves ink off plastic right away. Rub a little of it on the manufature and expire dates on the plastic bottle it comes in, and watch the numbers disappear. It is oh so effective for what it is itended.

[Gravelier007]

Personal preference. I never spray DEET on myself or the grandkids. I always spray it on my hand and rub it where it is needed.  I hate spraying anything where it might get in my eyes or inhaled. The only thing I ever spray is the back of my shirt. But I take it off first.

[Wild Dave]

some types of clothing to. while i have yet to bike tour i can usually out hike skeeters, even the thickest clouds.
 when i stop to eat or camp i put on my rain gear, they can't bite through nylon