Im sure youve all had this problem before, after tabing out to desktop. Rather then reloading your game you can do this

Go to console by pressing ` key
(dont have console enabled? press Esc then click options - Keyboard tab - Advanced - Enable Developer Console)

type in "mat_bumpmap 0" will lock up for a few seconds

then if you want your shine back type in "mat_bumpmap 1" lock up again for a few seconds

Will this fix sprays?

nope.

I laugh when that happens