Oof.  Shit, you can't even drop the plastic ones in a bucket of acetone and decide you like a different chapter better can you.
I had about 3000pts worth each of DA, IG, and genestealers (tyranids were barely a thing, I had a few plastic warriors and a (the) carnifex), at the time that worked out pretty well for big games.  Guardsmen?  No, those are Brood Brothers today.
All off the back of this guy here looking cool.

https://i.poastcdn.org/d029539c2fbdf12efeb1e44b40c770248f17a3751f6f501a1d786a84f0860d8f.png 

 You can strip plastic with ovencleaner 

 Good to know, learn something new every day. 

 At least back in my day...test your oven cleaner beforehand tho. 

 Obviously, I would never have thought to try it though.