i gotta bad habit. I like all the music on my old tapes, even those tapes with bad 'sss'. And i insist on playing them.
So i refuse to dump those bad tapes if they got good tunage on them.
So i play them anyway and have accepted that i'll just have to constantly clean the heads/guides/etc if i want said tunes to sound their best.
Some of the absolutely best sounding r2r tape i ever ran into was 'audiotape' formula 15 (orange coloring on box). I used them from 1973 til '75. Imo, this stuff sounded better on my sony 277-4 and a teac 4010 than maxells or whatever else i could get ahold of back then.
But 36 yrs later, we're talking major 'sss'!
when i went to play my quad version of 'the sound of music' (on said form. 15) last month, it still sound really great but i had to stop and clean about every 15 mins.