i use megs ultimate wash and wax, megs wool mit, megs water magnet towel and the megs quick wax or quick detailer after drying. all my towels, applicators and mits are thoroughly cleaned after each use.
the specks are just winter road crap such as tar and grit etc. probably not as much tar as when i rub them they come right off, not smear in like tar usually does.
they come off easy enough by rubbing them but as they are so many its quite laborious so wanted something to loosen all the tiny specs off before/during washing.
would snow foam loosen these off.