Die Deterioration Doubling manifests in many forms. On nickels it is most common as build-up on both sides of the letters. On zinc cents it can be shadows, or ridges on the inside or the outside of the letters, build-up on the inside or outside of letters, or build-up on both sides of the letters. Important to note is the following:
1. It has none of the characteristics of hub doubling (doubled dies).
2. It happens on late die state dies. There will be flow lines present.
3. It generally always affects only the outer part of the design.
4. It usually has 'softness' and is not well defined on zinc cents.