Is there more than one type of deteriorating die doubling?
Inside Abraded Die Doubling is caused by wear at the edges and inside the design detail. It appears as an enlarged, irregular outline overlapping the original design element. Outside Abraded Die Doubling is caused by wear at the edges and inside actual detail. OADD does not overlap the original design.
Is the 1955 Poor Man’s Doubled Die Lincoln cent a result of hub doubling or deteriorating die doubling?
The Poor Man’s 1955 doubled die cent, as well as doubling encountered on many other Lincoln cents after that date, is a result of deteriorating die doubling.
Would you clarify what is improper cleaning?
Any cleaning to which a coin is subjected is improper cleaning. There is no upside to it. It will decrease the value of a coin. Don’t confuse this with restoration, which should be done by a professional service. Even restoration may not necessarily add value to a coin.
I see coins advertised as being housed in third-party certified slabs called a “rattler.” What are they talking about, and is it important when buying such a coin?
Some of the earliest encapsulations were crude by current standards. Coins might be able to move around or rattle in these cases, unlike the cases now used that secure the coin more tightly. The reason some people prefer these coins is due to their understanding (or misunderstanding) that the coins might have been graded using a tighter grading standard than is now in place.
Is it true that tighter grading standards were used by third-party certification services in the past than they now are?
Third-party certification services try to be consistent at all times, but being that coins are graded by humans rather than by machines, the quality may unintentionally vary periodically. The major services have sets of coins they use to illustrate the grades to be assigned. Graders are expected to review these coins periodically.
Should I avoid purchasing replica coins?
It is up to the individual if replica coins should be collected or not. Perhaps a key date you are pursuing is so expensive, a replica might satisfy fulfilling your set. One thing is certain: ensure you purchase a replica with your eyes wide open. Replicas are worth no more than their intrinsic value when being sold to a dealer.