I have a 5/8 Ralf Aust and the SRD 2" Latigo strop that I've been using for a couple months now. I'm noticing after I strop that there is just a hint of black film on the spine after I'm done that wipes off with a tissue. I think the razor is taking off tiny bits of leather as I strop and it's being deposited on the spine. Is that normal? Is it an indication that my stropping technique needs some help?