I have taken my well used coarse DMT to a new woven fabric strop to soften the top of the bumps.
I am a fan of a single modest application of a submicron spray.
Chalk is interesting... It varies a lot and can contain a little or a lot of the micro amorphous siliceous
bits from sponges, diatoms and more (can be good). I once read that the 'ultimate' edge for a steel
microtome blade was had by using diatom rich chalk on a vibrating glass plate/table.
Talc today should be so pure and soft that it might best be used to smooth a strop and reduce drag.
It should be a do not care on canvas or nylon webbing. Hairspray or spray starch combined
with talc or good chalk might fill in the fabric nicely.
I have an old shell strop and the canvas is both much finer than newer strop fabrics but was
also fully fixed with a grout like chalk? filler. It has minimum 'buzz' when the spine runs over it.
I like it.
The SRP strops make replacing the fabric easy as pie. Try stuff even the back of a strop.
The back of a fabric strop is an ideal place to use 'stuff' like CrOx that the razor only needs
to see once in awhile.
The coarse modern canvas strops are one reason I love the hard wool strops so much.
My Illinois 127 strop took a lot of abusive break in and now is almost black and has an
almost polished surface with a lot of submicron abrasive in it. The black is oxidized steel
that now contributes to the polish and abrasive on the strop. Iron oxides are harder than
steel.
I am old enough to have used slate blackboards and had to clean erasers outside on a
corner of the brick building. If I had some of that chalk dust it would be on my strop yesterday.
Most chalk today is gritty and would not see my strop.
A spray starch and spent slurry from a 10+K japanese hone might also condition the
back of a new strop. If you like it go for it.
Two types of strop in my set, dirty black and finely abrasive very very fine that I reserve for
the first stropping after honing and nice and clean for after first shave on until the the next time
I hone.