Descriptions from Tom Byrne's Coaster Book published in the early 80's
MINT: The coaster is absolutely
flawless. No stains or
discoloration No printing errors
and no frayed edges
GRADE 5 (Filler): A grade 5
coaster is one with corners that are
bent or broken off. Stains that
obliterate part of the writing on the
coaster or nail holes that have split
a corner of the coaster make it a
grade 5. This is the type of coaster
that you should definitely upgrade
as soon as possible. If you erase a
coaster to the point where some of
the ink is removed, it is a grade 5
coaster
GRADE 1 (Very Good): An
excellent coaster that has a slight
printing error, tiny frayed edge, or
minor spot of stain. A tiny pin hole
on an otherwise mint coaster
would drop it to grade 1
GRADE 4 (Poor): Large nail
holes with bits of paper
shredded off near them are
signs of a grade 4 coaster.
Definite stain marks, warped
edges and burn marks make
coasters into grade 4 condition.
Coasters that have writing on
them or bad mildew spots will be
in this grade
GRADE 3 (Fair): This grade probably
is the lowest grade that you would
want to buy. It may have overall
fading and stains from being used.
There are certainly rough edges with
dents or creases at the corners. One
or more nail holes will bring a clean
coaster down to a grade 3