Get one of those plastic storage containers sold in the super stores and some garden centres with a lid big enough to fit an old ice cream tub inside.
concave some wire mesh into the ice cream tub before you wrap it over the edge, part fill the ice cream container with 1cm of water and lay a normal sheet of kitchen towel in the howl on the mesh and place your wax on top. Put the lid on the larger container and wait.
As the wax melts it will seep through the kitchen towel and into the water below and will be nicely filtered.
Picture is when I made a 10-12oz block for my associations honey show last year and I won 1st prize using the above method first before remelting it again into the pyrex bowl to make the wax cake.
I have just made one using a timber shipping box. I was working for a company who received components in from around the world, and chucked away these boxes afterwards, so it was just a matter of waiting until a small one came in and grabbing it. If you can get your hands on one, they are very useful. It even came pre insulated and is made from 1" timber, so should last a good few years!
I have the glazed panel for the top, I just need to work out the metalwork, or possibly use a silicone baking sheet to run down into a tub. I was going to filter by putting the wax into a pair of tights.