Grammaretto. There must be lots of people who would welcome sheets etc, but finding them is difficult. Charity shops do have them for sale. I have taken mine there. And have given a friend with horses and DD for her dog drying some old towels.
I had single size plain coloured duvet covers , duvets and sheets and managed to pass them on to friends whose had GC. They were all in good condition, but the towels were more worn. Fine for dogs and horses.
Would a local church welcome sheets etc for parishioners who are short of cash. Could you ring your local church and ask? A shame for good things to go to waste