If you have had a tin of shoe polish for a while you may have noticed that is has dried out and cracked, this is because shoe polish is composed mostly of solvent, and solvent evaporates.
When the solvent evaporates it leaves the wax in the tin, and because there is less volume the wax begins to separate and crack. The wax also becomes harder because the solvent was keeping it in a softer paste consistency.
This process can be reversed by replenishing the solvent and melting the wax, all within the tin.
This can also be a somewhat dangerous process as the solvent can be flammable. The most common solvents used in shoe polish are Naphtha (a petro-chemical) and Turpentine. Both have a flash point below 100 degrees Fahrenheit, so they should be handled with caution around open flame.
I would also suggest turning on your stove hood fan, and avoid inhaling the fumes as much as possible. It is also a good idea to have a flat surface object (like a cutting board) available to smother any possible flame. That being said, I have never had shoe polish catch on fire without being exposed directly to flame (although it is possible).
For the most part this process may be more work than it is worth, but that is something you will have to decide for yourself.
First select a solvent to use in replenishing the polish. Turpentine is readily available where you would buy paint, but I prefer to use orange oil because it smells better and has a higher flash point. You can order orange oil from a number of places on line. Either solvent will work.
To revive your polish do the following steps in order:
- Observe the amount of dried up polish in the tin.
- Pour in solvent at about 25% to 30% of the volume of the existing polish.
- Fill the bottom pan of a double broiler about three quarters full of water.
- Put the top pan of the double broiler on top of the bottom pan.
- Place the polish tin in the bottom center of the top pan.
- Turn the heat up to about 50%, and let heat until the wax melts (this is where the IR thermometer comes in handy).
Beeswax melts at about 145F (about 10 minutes)
Carnauba wax melts at about 180F (about 15 minutes)
- Once melted to liquid, turn off the heat and let the wax cool (this may take up to an hour). You can lift off the top pan with the polish tin in it to speed up cooling, but be careful not to spill the polish out of the tin in liquid form (it makes a mess).
- Once the tin is not hot to the touch (below 90F), you have a good usable tin of shoe polish again.
If you want to give the polish a bit of a cream texture add just a few drops of coconut oil (less than a quarter teaspoon) while the wax is melted.