TTCombat makes some excellent and fairly cheap resin kits with 'backyard scatter'. But it would be too expensive to make the amount of bases I would like.
So I've taken some Green Stuff World blue stuff and made molds of the resin bits, then I've cast extras with plaster. This is super duper cheap and you'll get 5 kg for 12 Euro. And so I had extra trash cans and garbage bags quickly.
Glues the bits to thin plastic card and cut them out.
I base coated the piles with grey spray and picked out some different details on the bits. Then I gave the piles a heavy layer of brown wash.
Then add extra details to the base with printed news papers, torn up toilet paper, pieces of black plastic and shredded cork pieces.