I have a no1 honeybrown heirloom that I use regularly.
I also have the starter strop that came with it. it has a hard, brown surface.

After some experimenting I discovered that the starter strop is quite good at refreshing a blade that is getting dull.
I have tested this with my Joseph Rodgers frameback that I honed several months ago.

It hasn't been touched up since, but I have found out that if it gets too dull, I can strop 30/40 times with some pressure on the starter strop and it is back to shaveready.
The heirloom doesn't do that. it can only smoothen an edge that is sharp, but once an edge is getting duller, there is nothing it can do about it (with my rather basic stropping technique, that is)

The funny thing is that I haven't treated the strop with anything, so it must have some inherent abrasive qualities. It does make a rasping sound while stropping.

Anyone else have similar experiences?