There are no rubber items but the deflector's opening is done by a wax pellet that might be damaged by some chemicals. Try taking the unit apart. The spring's first, then there's a stamped hex nut inside that requires a crows foot wrench to undo. The rest comes apart easy enough. I dip sometimes then bead blast and paint. When I re-assemble mine, I "adjust" the deflector to un-heated air. Somehow you just don't need one in California.
Jim