Kind to share your experience, Robert, but IMO there are better
resources for this kind of stuff than MicroMark. :-)
MicroMark is a convenient source for some things that are difficult to
find. They specialize in selling small items that they buy in bulk
cheapo and break them into packages of 10 for big profit. Basically the
Tandy Leather approach for a supplier of stuff for model train
hobbyists. If you like them, keep buying from them, but you might like
to check these other two options.
Several years ago Amazon acquired the "Small Parts" company. In my
scientific days they were the go-to source for anything small and weird.
I used to buy tiny ball bearings made of a number of different materials
to use when I made medical x-ray machine image quality test objects.
Nowhere else could such odd-ball items be found. Unfortunately when
Amazon absorbed the company they got rid of the Small Parts web site
which was very convenient to use. Now you have to spend some time with
Amazon's clunky search engine.
With a little patience searching Amazon for such items, including the
words "small parts" will yield a bounty of items, such as: