In article , John Martin
writes
I've spent an afternoon clearing moss from the gutters and off of roof
tiles. I've got buckets and buckets of the stuff.

Can I compost it? Or should I save it?!

Compost it. It will not provide much bulk, but it is high in nutrients.
If you are setting up hanging baskets it could be used, but ex-gutter
moss tends to carry a lot of dead leaves etc.
--
Alan & Joan Gould - North Lincs.