Step 1
Clean crayon wax off of polyurethane by rubbing a little toothpaste into the mark with a soft brush. Wipe the toothpaste off with a soft sponge, and the crayon mark should come with it.
Step 2
Remove candle wax by using a hard plastic scraper to get as much of the wax off of the floor as you can. Work from the outside edges in, to avoid spreading the stain. Hold a plastic bag full of ice on the wax for two to four minutes, until the wax becomes brittle. Scrape the rest of it off with the plastic scraper.
Step 3
Clean up wax of unknown origin by melting it with a blow dryer, which does not get hot enough to damage polyurethane. Pour a dime-sized amount of mineral spirits onto a clean, absorbent cloth and scrub the melted wax until you have removed it all.
Step 4
Strip floor wax from polyurethane with a chemical stripper designed to be used with a mop. Read the label to find one that is formulated for polyurethane. Usually, you will dilute the mop stripper with equal parts water, and then simply mop it into the floor, wait a few minutes while it dissolves the wax and then mop it up again. Dry the floor immediately, because standing liquid of any kind is not good for polyurethane.