Clothing treated with Permethrin is said to work well in repelling bugs, but I'm not sure if it's repellent qualities extend to one's face, neck, unprotected arms, etc. But, at least the little buggers won't bite thru the clothing.
As for DEET - I always put mine in a Ziplock, but now do a double Ziplock system. A few years ago the single Ziplock developed a small hole, and somehow the container was activated, and a small amount of DEET bored holes in my Precip jacket. Fortunately the holes were near the waist, so it didn't impact the usability of jacket.
