Slabs

I've heard some people use a Dremel tool!

there is a video on youtube that shows a really easy way by using lock cutters(i think that's what they are called)

Note that if using a tool like a Dremel, there are many other things to consider. For instance if the tool is a variable speed tool. The type of cutting off wheel. Same with any power tool used to cut open a slab. Those slabs are plastic and any tool using certain cut off tools, such as a thing called a cut off wheel in a Dremel, if used at high speeds, makes the plastic melt back together as fast as you cut it. Dremel does make miget circular saw blades that work but again at high speeds, melts the plastic back together. Similar is a saber saw, reciprocal saw or even a regular circular saw. The speed and type of blade is important. For most power tools to be used for opening a slab, they should be a variable speed one and used on a slower speed. Any cut off blades should be an average toothed blade not a metal cutter or harsh, large toothed wood cutter. Just cut off several sides and they will just open.
The usage of bolt cutters, pliers or other similar tools could have pieces flying all over the place.
Of course a Butane torch will just melt the plastic off completely and leave a well coated coin.