In general, we always recommend testing the products on a concealed area before first use to see how the products behave on the leather as we cannot guarantee 100% that Glowbag will work on every bag. Leather is a natural product and has always been chemically pre-treated in some way. If the cleaner is absorbed directly into the leather, we recommend moistening a cloth with the cleaner to carefully remove stains. The same applies to the conditioner. If the cleaner remains on the leather, it can be sprayed directly onto the leather and the brush can also be used.