Well, first step was to pack all the wax down into a saucepan and add enough water to cover the wax. I boiled it for about an hour, then poured the whole mess through four layers of window screening, which filtered out all the big chunks of crud. Once the liquid cooled I had some (very dirty) water and a semi-clean wax patty.
The second round, I replaced the dirty water with fresh water, boiled it just until the wax melted, then poured it through the window screening again. At that point the only non-wax material left in the water was fine dirt which seemed to naturally sink to the bottom of the wax layer, so I kept it over low heat for about fifteen minutes just to let it settle, then let the whole thing cool again.
The final wax patty was just like you see except there was a thin layer of settled dirt on the underside, which I scraped off with a knife. What was left was nice and clean.
I hear that a lot of people use pantyhose or old t-shirts for the final straining, but I didn't see the need. Melting it in water twice was enough to get the pure wax to rise to the top without impurities. I'm sure it could be a bit more pure but it doesn't *look* dirty which is really all I care about
