Wow, I guess ScotchGuard still exists. I grew up with the old commercials where the kid would spill on the scratchy, rust-colored couch and mom would make the "Oh, no!" face, but then the sorry child would just wipe up the soda and everyone would smile.

Since that looks like it's more for actual waterproofing than DWR, I may try some. I don't sweat much from my forearms, so losing some breathability there should be tolerable.