save them. you can make hash oil from the stems, hash from the leaves! check other areas on this site for the making of these wonderful things. all my schmoking life i'd been tossing stems, but now (and I've already made a few batches) you can make hash oil from the crap you'd normally throw away. so now I save EVERYTHING, from my (bought) bags, I save stems, to my pruning leaves I've cut from my plants. everything will eventually be used for various goodies. stems and leaves can also be used for cannabutter. read 'recipes' on this site for these things.