I have recently been working on a collaboration with Kitty Love of Asheville - on a phoenix and woman art nouveau styled painting. When she showed me how to use gold leaf size "glue" - properly and not to ever touch the craft gold leaf I had.... I learned using tweezers to move the gold leaf around, a razor blade to cut it in to small pieces, and a cloth to rub it down, made all the difference in my art nouveau work.
I needed not to touch the gold leaf, (ever) since it was craft - not real gold leaf - it would tarnish within a few days or weeks of touching my fingers! I learned the hard way, having to redo most every gold leaf area I had done. I am interested in purchasing the 23k gold leaf now for it never tarnishes. Make sure to seal your gold leaf immediately with the gold leaf sealer - a clear coat that will protect the leaf from oxygen and oils. Silver leaf and gold leaf works best on flat hard surfaces. Make sure the 'size' or adhesive is clear before attempting to leaf it. Vacuum up gold leaf particles afterwards otherwise they may attach themself to your cat's fur :)