[Mr. 16 gauge]

Found some Remington "sportsman" steel waterfowl loads a few years back that had just fallen out of someone's pocket (I assume....the brass was still nice and shiny!) while I was pulling my boat over the dike. I took them home (IIRC, there were 3 or 4 shells) and cut 'em open.

I found pretty much the same thing that you found.....shot of various "sizes" (I hesitate to call them sizes, as not a one was round!), the pellets themselves had rust on them, and the powder was damp (remember, these were found on a dike with shiny brass).
The pellets looked like remnants swept off the floor. I don't know why people feel they are getting a 'bargain' by buying this crap, but I wonder how many of these rounds cripple, instead of kill, their intended targets as opposed to high priced (or higher quality) steel loads.
After several years of poor performance, I decided to reload my own steel shotshells, but he year prior to that I tried some Winchester Supreme steel shotshells.....a little more pricey, to be sure, but they did KILL the ducks I shot at instead of just crippling them.