My SIL has given in the past:
Books that we lent her, in perfect condition, back to us (but now with scribbles on every page, and torn pages)
School workbooks for writing in (all pages written in)
Clothes covered in stains, and smelly, not even washed
Shoes worn to within an inch of their lives, still with mud encrusted on the soles
Broken toys
Can't think why we don't see her anymore. We always thought she couldn't be arsed to take them to the charity shop, so it was easier to dump them on us. Either that or she was just doing her passive aggressive shit.
There's nothing wrong with passing on second hand items, god knows there's enough waste in the world, but making sure they're clean and working; surely that's just common decency?!
Some people aren't like that though. We bought a pair of shoes on ebay said 'worn once, in perfect new condition', when they arrived, the bottoms were covered in mud. But I guess maybe she wasn't lying, they were worn once, just in a muddy field...