1985-P Nickel Reverse, Is This MD, Die Deterioration Or ?

MD ( Machine Doubling), happens when the die is loose and moves a little extra at the strike. The extra movement alters the strike it originally made. Depending on the extra movement, it can leave part of the devices flattened. In so doing, without counting the flattening, the devices are smaller (reduced in size) or it can just barely touch them and just leave a "line". MD Follows alongside the devices and is the same color. When viewed from it's edge, it shiny. The shiny edge usually has striation lines from the movement. It's more easily seen with magnification.
Die Deterioration is from wear on the die. The more wear, the more extreme it's effects on the coin is. It usually shows toward the rim side of the devices. Light wear on the die leaves it close to the devices and more "formed". It's not flat and crisp like MD, it's less defined and mushy. The more wear on the die, the bigger and sloppier it appears on the coin. The devices themselves can become larger and less defined. It goes with the die flow toward the rim. You can usually see die flow as lines in the fields pointing to the rim, it's planchet metal moving to the path of least resistance (worn areas on the die), like the perimeter. Other ways to recognize a worn die besides or in the absence of the said lines are wavy perpendicular to the rim lines, and another can be an overall "orange peel" effect in the fields. It has a multi small bumps appearance.
The most sought after Doubled Die doesn't reduce the devices, it's not made from part of them as MD and DDD is, it's on the die next to them. When counted, it enlarges the devices. It's also higher in relief than the worthless doublings, it's almost as high as the devices, and is crisp.
The fourth factor you have to consider is wear on the coin. Letters on the die are wider the deeper they are in the die. On the coin the tops are smaller. As the coin wears, the letters become larger.
I hope this helps Joe.

A lot of coins have a mix of worthless doublings. This one does too. The easy part is when you do see a nice Doubled Die. It'll jump out at you and say, "no doubt about it".

I understand completely. It sounds like a lot to remember, but it's so redundant it won't take long.
As far as the ones that jump out, I still keep an eye out.
It would be easy to miss an easily recognized doubled ear if we don't actually look at it. I always search all coins for clashes and such, but keep an eye out for special dates. For instance on cents 69-S DD0 84-P Ear DD0, 95-P DD0, 94-P Columns DDR, 83-P DDR, etc. That comes easy too with a little time. It too is redundant.