Years ago I used to check for and collect tagging varieties such as tagging shifts, wavy tagging and various tagging errors. I was also into hi-brite papers, stamps with hi-brite backs, coloured spots on stamps, minor colour shifts, and all kinds of minor stamp errors. It was a bit of an obsession for a while. It's amazing what you can find if you look carefully at every stamp. I have pages of that sorts of "fly specking" stuff. I have kept the major things I found - the missing bird on the totem pole, some major perf shifts, a printed on gum side, a few one bar Ottawa taggings, a few miss-cuts, several Vancouver skyline varieties, the Kreighoff errors, and a few other oddities. The rest has to be gone through and sorted but I'm not sure what to do with most of it. Does anyone out there bother with this minutia? It used to be almost an obsession that I'm glad I got over!!