Yes, @grk , I have seen it. My ’platter mat’ is a slab of graphite, and it adsorbs contaminants. I noticed a dark patch on the graphite after placing a piece of silicone damping material on it. Since then I’ve discontinued use of Zerodust too.
Fortunately, whatever it is, is tightly bound to the graphite, and so unlikely to contaminate the records.
Fortunately, whatever it is, is tightly bound to the graphite, and so unlikely to contaminate the records.