Grades represent the amount of wear on a coin mostly and for uncirculated coins the grades reflect strength of the strike and surface blemishes (scratches and nicks). The higher the number grade, the better the coin is. Grading is a little more complicated but this is the basic concept.
about good, good, very good, fine, very fine, and extra fine.
It depends how much you have and what type of coins you have. Are they collector coins (as in, high grades, key dates, rare coins) or are they junk silver coins (as in, worn silver quarters from the 40s, silver dimes from the 50s, etc.). If they are collector coins, it is better to sell to a reputable dealer. If they are junk silver coins craigslist and eBay are your friends, but dealers and jewelery stores will usually buy them too. Don't go to places like "Cash 4 Gold" or other "Hotel Lobby" sellers. They will often times take 50% or more off the true value of your coins.
No D's in 1928. The coins were only struck in Philadelphia and San Francisco. The S coins run from $30.00 to $70.00 in circulated grades.
All circulating US silver coins were at least 10% copper. Pure silver is far too soft, so it has to be alloyed to stand up to circulation wear.
The U.S. Mint does not assign grades to any coins it sells. But Proof and Uncirculated coins do have different grades.
The BU stands for Brilliant Uncirculated for all coins not just Morgans dollars.
Modern "silver eagle" coins are 99.9% silver, which is about as close as you can get to pure silver using normal refining techniques. Old silver $1 coins (1935 and earlier) are sometimes confused with modern eagles, but they're not the same. They were made of 90% silver to stand up to circulation wear, and contain about 24 gm of pure silver with the remainder being copper.
All coins come from a mint. Casino coins are sometimes solid silver.
No British circulating coin has contained any silver since 1946. From 1919/1920 to 1946, all British silver coins contained 50% silver. Prior to 1919/1920, all British silver coins were made from sterling silver or, 92.5% silver.
There were proof sets made in 1974 and 1975 where all 8 of the coins were silver, and proof sets made during those years when none of them were silver. Assuming that your coins are in a set, check the 1 Cent coin - if it looks silver, then all the coins in the set are silver; if it looks bronze, then none of the coins in the set are silver.
Just recently with the advent of bullion coins such as the American Silver Eagle. Coins intended for circulation were never 100% silver because silver is simply too soft of a metal for coinage. They were 90% silver in American coins until 1964 for dimes, quarters and half dollars, but other than bullion coins, no coins are made of 100% silver.
Silver coins are typically shinier and have a higher metallic sound when dropped compared to pewter coins. Silver coins are also heavier than pewter coins due to their higher density. Additionally, silver coins may have distinct markings or engravings indicating their silver content.