Condition information is based on Redline Hot Wheels.  I do not include toning issues in grading unless it is serious.  Redline Hot Wheels were originally polished then painted.  When air and moisture can reach the metal under the paint then the turn dark like brass decorations do. 

Matchbox cars are usually either played with or not but I still use this basic grading outline.

Mint  you will not see a strait out mint listing on any of my cars.  Mint condition implies perfection and no old toy cars even in the package are perfect.  I simply do not use Mint as a rating.

Mint - yes the line next to mint means mint minus. I use this rating for any car that approaches perfection or looks factory fresh.  Cars that come from childhood collections rarely can be rated
Mint -, even blister pack cars have flaws.  But a tiny factory flaw is passable under Mint - .  Typically all collectors prefer to keep anything that is this fine.  When I started collecting in the 1980's through about 1997 I kept all of the Mint - cars for my collection and sold the others.  Most come from opening packages.  In a collection of 48 cars you may get one or two.  Few collectors can display as many Mint - cars as I do here on the Toy Car Collector and they are for sale!

Near Mint  is a car that may have been in a collection but survived with little contact with hands.  Usually the best you can find because Mint - is so much more scarce. 

Excellent  this is usually a real nice car you find in a childhood collection.  Some paint nicks or rubs but a nice looking car overall.  This is the condition that I see the most of and can be acquired easily.  Better condition is hard to find, and lesser condition cars are still prized by the original owners who most often value them like mint cars so I can't buy them.

Good  a played with car showing wear

Fair  a played with car that shows lots of wear, still displayable.