Yeah, that magnet is awesome. I scrape it every time I go into a TD. Just watch out for pins. I think the magnet also accounts for all the extra clad that gets counted. In branches where the tellers haven't cleaned the magnet off in a long time and there is big bulky stuff stuck to it it sometimes blocks all the clad U.S. coins from falling into the hopper. I usually try to go into dump when they are relatively busy and I always bring enough to trigger a bag change. As soon as it says the bag is full, I pull the metal thing out, scrape all the funny money off and then tilt the metal chute both ways so that any extra clad falls out into the hopper.
Once they come to open the machine I also check the little shelf inside the machine that tellers sometimes put random coins on and then I check all the way up the reject tube. Some of the reject tubes aren't angled right and extra coins (and sometimes silver) get stuck pretty far up the tube. Finally, when I first start dumping, I let the machine run for 10 seconds or so to listen for anything stuck on the actual wheel since sometimes the machines will have large dollars stuck in them. If I here something stuck in the machine I ask the teller to open it all the way because I think I may have put a large dollar in it by mistake.
Tim, where is this second magnet? I haven't seen this one yet and I've spent a lot of time studying these things. TD machines are a pain to dump a lot of half dollar volume into, but they are great for all the free extras you get out of them.