The heat method Rodney posted works very well, but may take a bit of practice to get the hang of it. You should try it on a test piece first. Apply just enough heat to flow the epoxy. Don't over heat or you may blister the epoxy. I do recommend you try this to see if the heating method works for you.

As for solvents, the rubbing alcohols work, but other solvents are much superior for thinning epoxy. The best one is probably MEK, but it can be hard to find and is nasty stuff. Auto body paint stores will carry MEK and sometimes it can be found at hardware stores. Next, I'd select acetone, which is easy to find. Then 100% methanol, also easy to find. Then denatured ethanol, no water. An lastly any alcohol with water, which will basically be every alcohol found in the drug isle.

If you locate the MEK, a plus side is that it will effortlessly clean covering adhesive off of anything, irons, smears on the covering, etc. But regardless of which solvent you use, it should go without saying that you need to take proper precautions, gloves, filters, ventilation, etc.

Edit - Another solution is to use a laminating or finishing epoxy. This type of epoxy is inherently very thin. It has the viscosity of very warm cheap syrup. It will easily brush on. No need to mess with heat or any solvents.