The normal "organic" bin is for anthing which can't go in any of the recycling bins. Stuff such as left over food, the contents of your vaccum cleaner, etc.
No need to package in any special way. Most people just put it all in a bin bag and dump it in the "organica" bin.
Those that don't bother recycling just dump everything in the organica bin .
I don't know the Rota area but thirft shops aren't that common in Spain so not sure if you have one there. Many of them tend to be run by expats so many ask other expats in the area, that's probably your best bet.