I just take a dremel and grind out the innards. It really does not matter if there is some release in in places (unless you have a clear top) There will be enough glue to glass connection to make it stick forever. The easier solution to using a clear glass is to use a tiny pastel base, of any color, and build the clear on top. You will hide any traces of release this way.
When you glue them in, just stick them in a piece of foam, poly-clay, or a cork board
