Yes. if you have a Stagbreaker, or better yet, a wishbone, you can find muddy scrap piles buried in the ground outside in the swamp. I went back & revisited a swamp I had thought I cleared a while ago, only had 2 crypts in a decent sized swamp.

Went back just today with the wishbone equipped & found about 10 scrap piles all outside that simply had to be dug up in order to be retrieved. Only about halfway through them currently, but have about 40ish or more Iron Scrap just from digging them up. So it can be done this way too.

If you don't have the wishbone however, it is a needle in a haystack trying to find them.

Also Oozers have a % chance to drop them when you kill them.