I use my hands because I never forget to take them with me. A friend of mine has an ugly 8-ball grinder and it's turned into a sport to try to steal it for as long as possible untill he starts to miss it. I do think crumbling weed by hand is best. It takes pretty long sometimes, but if you have proper dried weed you might have it completely crumbled in just three or four "moves". I like it bette rthan scissors because it actually breaks it up in tinier pieces, dust if you are really going for it. There's a limit to how intense a grinder can grind because of the distance between the sharp-ish thingies that actually tear the weed apart.

What am I talking about.

A razor, really? never thought about that one, lol