In The Practice and Science of Standard Barbering by S.C.Thorpe

Thorpe describe canvas strops of high quality linen or silk woven into a fine or coarse texture utilized for putting a lasting edge on a razor.

He mentions rubbing a bar of dry soap over the strop and working it well into the grain of the canvas before rubbing a smooth glass bottle over it several times to both force the soap into the grain and also remove any excess soap.

Any beta on conditioning a linen or canvas strop
What kind of soap do you think Thorpe is using?