I've used a length of 1-1/2" PVC pipe rubbed with a piece of fake fur or one of those fake lambs wool car washing mitts. PVC can generate some serious static electricity. I tried the foam block (that's from the GMR video on Lance Mindheim's Monon layout). It works fine, but if you have a lot of grass to do, you wear all the hair off your forearm from rubbing the block on it!