Soldier equipment mods, what works?

Modern soldiers are given gear and they modify it to suit their needs, this has been a common practice since, probably the first issue of military gear. Condoms on rifle barrels, slits in camo to accommodate pieces of brush, socks used as goggle covers, etc.

I’m fascinated by the way ingenuity re purposes even the most mundane items, into efficient solutions.

Militarily speaking, what has been modified into what? Any war or era is of interest to me.

My Dad said that WWII Gas Mask bags were a good place to stash your cigs, after removing the worthless mask.

Masking tape with horizontal slits on binocular lenses - to reduce reflectivity I assume.

Source - Band of Brothers a fictional HBO series but I’d bet its accurate.