There is a small wood on the opposite side of a footpath from one of Loughborough's newer housing developments, with a clear trod through the wood even though there is no public access. [In recent years there has been a repeated sequence of signs being put up to deter access, then the signs are vandalised, and after a while replaced by new signs.]
I was walking through the wood on Monday when I came upon the remains of a party: charred remains from a wood fire, around which were scattered drinks cans, a few plastic bottles and some broken glass; fortunately not too much of the latter. According to the Trespasser's Companion https://www.trespasserscompanion.org, one should pick up litter while trespassing; I do in any case sometimes pick litter up on my walks. So today I went back with a small rucksack and collected most of the drinks cans, plastic and broken glass, but not the charred stuff, and I certainly didn't manage to clear up every piece of plastic or broken glass. There's someone in our Male Voice Choir who sells waste aluminium for recycling and gives the proceeds to choir funds, so he will get the drinks cans.