I have some very valuable to me recordings that I would very much like to preserve for as long as possible. I mostly use Maxell Vertex back coated metal cassette tape with my Nakamichi 682ZX, but also some reference TDKs, though they are not near the Vertex.
At one time Radio Shack had a very nice manual cassette winding mechanism, which makes spooling the tape past a dispensing applicator very easy and straight forward. I have taken an older (inoperative but machanically good) battery powered cassette player and use it as a fast winder to move the tape past the Preservative applicator.
Thank you for your message, Walter