. My usual is 3 whacks with a hammer to the flat sides, repeat as nessesary with good judgement on the force of the next blows until she cracks. Or I just put it in the safe door & close it to crack the peripheries of the slab around the coin. Take your time & it is not a big deal as long as you dont go ape sh&% & hit it too hard.
Wrap slab in old handtowel (prevents little pieces of plastic from flying around the room) Place corner of slab against concrete wall or floor Smack opposite corner of slab with a hammer (some are more tenacious than others and require a beating) Check after each strike for progress until the two sides separate from each other and can be pulled apart Remove inert inner holder & coin together With palm under coin, catch the coin by bending the inert inner holder until coin comes out Shake towel over garbage can to get rid of plastic debris Never damaged a coin and smashed all tpg slabs without a problem. I like the vise idea above as it would give you more control. I'll try that next time.
I personally use an old Nokia phone. I tried a hammer once, but it broke... you shouldn't have the breakage problem with the Nokia...
I use the door of my safe to pop the seals open. No broken shards, no harm to coin. Just stick part of it in the gap between the door and frame and slowly open or close the door until you hear a pop. Once the seal is broken it opens right up like it was never sealed at all. Guy
One light tap with a hammer and it peeled right off. I believe I could have put it back together again. Here are some tomb free pics and a video if you want to check it out. http://s1288.beta.photobucket.com/user/jimbobstar/media/DSCN7458_zps6d9777b3.mp4.html
Those yellow ones have a tab in a slot on back, top edge of the holder. Just slip a small flathead screwdriver into the tab and it will pop right open.
The real key to this is that you must be both SMARTER and have a STRONGER WILL than the inanimate plastic case... But seriously though, a bench vise, and a 4-1/2" angle grinder with cutoff wheel. IF you still cant get it apart, call your local Mechanical Contractor and tell them you have a problem with a pipe. When the service guy gets there he will be more than happy to spend 15 minutes getting that baby open at $100/hour,,, I know I would be : )