I don't know if this would specifically work for toilet wax, but it will work for candle wax, so perhaps it's worth a try.
Get plenty of paper towels and your iron. Set the temperature to whatever is appropriate for the fibre in your carpet (wool, nylon, polyester, etc.). Place several layers of paper towels over the wax and "iron" the wax. The melted wax will absorb into the paper towel. Move to a clean area of the paper towels (or use new towels) and do this again, and again, and again.