The filter cleaner consists of a smart white protective case that splits in two to reveal a spring-mounted, square-shaped suedetté cleaning surface. I am pretty sure the inch square surface is impregnated with unicorn dust (or some carbon-based substance such as charcoal) as it worked like magic at cleaning my filters.
I unpacked all my NiSi filters onto the table and began to clean them one by one. The cleaning pad did not leave any residue on the filters. The process was quick and simple and worked like a dream. To be really sure that it wasn't a one-trick pony, I put thumbprints across the centre of the glass and with a quick wipe - swoosh, it was gone like magic.
A great little handy piece of gear to have in the camera bag for $20.00.