Some enamellers like to clean the copper at this point; however, in my opinion this is unnecessary as the heat from the torch will burn off oil and fingerprints. Yet, if you want to take this step, it won't deter the process. The exception for me is when there is obviously something on the copper that might cause problems.
If you are new to torch enameling or want a quick refresher, please refer to my tutorial on
torch firing opaque enamels
It might seem logical to discuss the "direct on copper" use of transparents at this point; however, I use a liquid enamel counter-enamel for that technique and we are not including liquid enamel techniques in this series.
Safety
This is just a reminder that you are responsible for safety in your own workspace. I can't emphasize enough the need for wearing a mask when sifting and wearing dark safety glasses when doing torch enameling. Clear safety glasses are not sufficient to prevent eye damage. I always have a quench bowl (receptacle of water) in my torch area, a fire extinguisher near at hand and work in a well-ventilated area where the fumes can escape. For this project, I am using a propane/oxygen torch. If you are making small pieces, you may find a large butane torch adequate and an oxy-acetylene torch also works as does map gas.