after daily long term use a canvas strop might need some cleaning.what i do with very good result is to use barber soap and a boar brush.work up lather on the strop and use the brush well.let it rest some minutes and rine of the latter. put it between a towel and squees out most of the water.then let it dry. mine looked as new after this treatment.
I have several linen strop components in need of cleaning. In the past, I've used a mild detergent such as Woolite® in COLD water, mild scrubbing with a bristle brush and rinse. Hang dry in the sun using one of these old wooden pants hangers.
i used the mugso real soap since it is mild scented and water at about body temp.thought about using a dish brush but decided not to because i think it would rip up the linen. i see i wrote canvas but ment linen