Yes, there a strong market for fancy serial number notes. Examples include very low serial numbers generally three digits or less, repeating serial numbers, and serial numbers that could be someone’s birthday or anniversary. Some Star notes will have a premium but depends on the series and signature combination.

1964 for dimes and quarters, half dollars saw a reduction in silver content in 1965 to 40% and continued through 1970 with that alloy.

Very few, most of the silver got sorted out in the 1960’s. The Hunt brothers attempt to corner the silver market in the late 70’s provided a catalyst for excessive sorting with silver almost hitting $50 per oz. I find maybe one silver coin per year in my change at best.

No, there has to be collector demand. Just as an example modern American Silver Eagles have had a big uptick in premiums this year while ancient Roman coins have stagnated or declined.

First place I go is the weight of the coin, a sensitive scale that weighs in grams is best. Most governments use extremely precise manufacturing methods. Even with wear a coin should be very close to its known weight. Secondly many counterfeiters will miss small details VAM World is an excellent resource for finding clues left behind from known die parings. Good magnification and light helps in this area.

Yes, provided they are certified by a couple select services. PCGS, NGC, and ANACS coins carry a premium and many dealers will buy these coins sight unseen based on these companies reputations and standards of quality. There are many other companies in the space but these companies are not broadly recognized and their slabs won’t likely carry a premium. Graded coins with a CAC sticker added will bring an additional premium.

Almost all cleaning methods will change a coins appearance and reduce it’s value. Chemicals and rubbing a coin will remove metal. Coins are struck at high pressure giving the metal a high natural luster, cleaning a coin will impair this luster. Coins can be professionally cleaned and restored both NGC and PCGS offer a service with proprietary methods. Grand Rapids Coins LLC is a licensed deal for both organizations and can submit coins for restoration.

Depends, there’s good toning and bad toning. Natural (not induced by a chemical or artificial process) rainbow colored silver coins with red, blue, green, yellow ,and gold colors are highly sought after by collectors. Having the obverse of a coin toned will bring more premium when compared to the reverse. There is currently a very good market for rainbow toned coins in the Morgan Dollar space. Darkly toned brown and black coins will usually decrease the value of a coin. Once a coin tones black it’s pretty much irreversible, known in the hobby as terminal toning.