Is this a fault in the manufacturing?

1992coin

Oldhoopster

Your coin is made from copper plated zinc and is suffering from zinc rot. This corrosion is similar to rust on the fender of your car. Its not a mint error. Spend it before it rots away

1992coin

The edge is eroded in and sharp to the touch. On the reverse side it has only the little bit on the bottom left. The craters go in the center and around the edges pretty deep.

Texast

Post mint damage. When it comes to collectable errors look at coins that don't have obvious damage to them, most errors of notoriety don't have a lot of edge damage that is easily determined to be from some other source they don't have cuts in them they don't have huge dings in the side you're going to want to look at an error book which will tell you what you need to look for.

If you're looking at modern coins the kind of errors you should be looking for are the ones that have been found already, in the case of the Close AM and the Wide AM cents that were issued in the 90's, I'm not sure about which ones are valuable but I know people are still looking for them.

If your looking to discover a new variety and make some money your going to be searching a lot of new coins, unfortunately most are caught by the companies that roll the coins and return them to the mint the only way you can get un-rolled, un-searched coins is by buying Collector size bags from the mint, you can get them for the quarter's, halves and dollars, none right now for lower denominations.

Hope that helps some

TexasT