Put on some heavy long heavy gloves for protection and cut them back to the base (you can dig/cut out the really gnarly roots if you want - they burn well). Then mulch them in with other tree cuttings in a shredder and use it on your garden. The canes are rich in sugars for fungi and slugs and snails hate the thorns. You need to pull up any sprouting chips over the next few months but they have no real root system so it's pretty easy - you do need to keep on top of them though. It does mean using gardening gloves forever in your vege garden as the thorns take a long long time to decompose but it's some of the best feeding and pest repelling mulch you'll ever use.
