Cleaning a rug with snow

Supposedly rugs were cleaned out in the snow in the old days. This is what I have learned about it, having tried it a few times:

1.  Wait for a good snow; several inches at least.

2.  Vacuum the rug first (or at least give it a good shaking out), and chill it, at least 30 minutes.  You want frozen snow, not melted snow.

3.  Wool fibers are weaker when they are wet.  That means being a bit careful with the rug, especially a flat-woven rug.  Braided rugs are weak in a different way, in the lacing that holds the braids together, so be careful with these as well.

4.  Spread the rug out on the snow, throw some snow over it, and sweep it off with a clean broom.  Alternately, lay the rug out dirty side down, and dance all over it (if you think the rug can stand it).  Either way, there is some agitation of the fibers, and some action that helps carry dirt off the rug.

5.  I have read that snow contains a small amount of ammonia, which helps get greasy particles out of the rug.  The cold also helps grease solidify and fall out.

6.  The hard part about washing rugs isn't washing them, it is drying them.  Especially for a very large rug. What I have done in that case was to carefully fold the rug after cleaning, bring it inside, and then gradually unfold it, moving it with each unfolding to a different part of the floor, so that nothing underneath it was damp for long. This method did leave some visible creases in the rug, though.

All that said, I did take our big living room rug (flat-woven wool) out into the snow and clean it recently, and I can't say that it made much of a difference. The rug does look about half a shade brighter, and sweeping it with snow probably did remove some surface dust, but this method will not take out visible spots or grubbiness. Still, I feel that it was worth the effort, just not by very much. Likely sweeping it indoors and then vacuuming it again (I always vacuum it without the beater brush) would accomplish almost as much.