I agree with mparker, too. The type of leather definitely has a telling effect. Some latigos seem to dull the edge, some enhance it like you would expect. The suede-type ordinary cowhide always seems to perform very well for me. You just have to lightly abrade the (untreated) surface with very fine (say 600 grit) wet and dry paper to raise a fine knap.

If your other strop works, then use it! No need for another one - unless you really want to treat yourself, of course!

Kees idea sounds likely too - you can''t tell how much fine grit is blowing about in the air, but try and develop a roll of black and white film and hang it up to dry in an unprotected environment and you will know all about dust contamination! If your strop was sticky after dressing and left so that it could have dust settle on it...

Regards,
Neil.