I had now idea just how dirty snow was, even when it’s not yellow. -K
A few days back I mentioned gather snow in the quest for micrometeorites. I have looked a all manner of things collected from melted snow, regrettably no visitors from space. What I managed to find was primarily biological, various pollen, bits of bark and leaf, and spores of all sorts. A few of the samples had sat around for so long before I got to them that some very interesting fungus had cultured. I found one clear example of Pestalopezia and several unidentified Deuteromycetes and Zygomycetes. The closest thing I found to a micro-meteorite was a bit of soot that I suspect is attributable to the wood stove a the gentleman across the street.
It really was rather surprising the amount of material which I did find. None of the snow I collected appeared as anything other than fluffy white powder when I gathered it, and the detritus which settled out in the melt water was ample to say the least.
vade mecum microscope 
Very interesting idea, I remember being allowed to handle a piece of moon rock at the science museum as a child. I wasn’t very impressed, it was grey and looked like any other old rock, but the memory has stayed with me so it must have registered as important somewhere in my childish mind. Perhaps if it had looked more like a piece of blue cheese I would have been more taken with it?
I have questions :-)
By micrometeorite do you mean space rock or space junk? And how can you tell which you have? Which is more likely?
Space rock, absolutely. The number of tiny meteors falling to earth on any given day far exceeds the number of bits of man-made refuse that exist in space or will ever fall out of orbit. Appearance and magnetism are the easiest methods of identifying a micrometeorite, there’s loads about them out there on the web and I’ll suggest searching as it’s not an area I know much about; an article about them in the March 2013 issue of InFocus by Josef Spacek was the first I ever heard about them. Some time I shall make a determined effort to find some.