If I have someone with me I just use the rope decocker and they pull the trigger, if alone I just shoot into a dirt pile or something with a field tip. There's a method to doing it by yourself by shooting it, but I haven't figured it out yet.
I have the same discharge target Mr. Gadget posted. It works well and is better than decoking bolts, IMO. I had a partial dryfire bc of a decking bolt and I've shattered several bolts shooting them into the ground.