As long as your cushions are dry and do not contain any odors or mold, you can donate them with your clothes and linens in a textile recovery bin (if you are donating to a brick and mortar charity like Goodwill or the Salvation Army, make sure to ask if they will take your cushion before dropping it off). Search the Beyond the Bin (https://recyclesmartma.org/beyond-the-bin-search/) directory for locations near you.