Nice coin, sir or madam. You have a United States trade dollar which were issued between 1873 and 1885 for use overseas. These coins carry no mint mark, S mint marks, and CC mint marks, and the CC is the most valuable (like yours!)
In average circulated condition, with scratches and stains as you describe, figure a catalog value of $50 to $200 US dollars, depending on the severity of the scratch and stain damage. You see damaged traded dollars a lot; the un-damaged ones are much more valuable. Be sure you understand what 'catalog' means. It is a weasel word, as explained under the Important Terminology link at the upper left.
Almost every coin dated after World War II is worth face value, nothing more. This applies to all coins from all countries worldwide, with very few exceptions. No circulating coins today contain gold or silver, although there are plenty of non-circulating coins that do. Non-circulating coins are often proof coins which are bought and sold in special packaging. However, most modern coins, even from exotic places, are basically worth face value except in a few special instances, explained below. Perhaps your coin is special, we hope it is.
These modern medals were, of course, struck in 1977 to celebrate Queen Elizabeth II's 25th reigning year. It's looks sort of silvery, but doesn't quite have the right shine in the pictures I can find. Some sources give the composition as 'white metal'. This usually means some non-precious base metal such as steel.
They were issued by the pharmacy chain 'Boots UK', at the time under the company name 'Boots the Chemist'. The design is quite pleasing and the medals are large and heavy, at 38 millimeters in diameter and around 30 grams.
Like all British coins, the reigning monarch appears on the obverse (the 'heads' side). King George VI appears in our picture, but your coin might be different. Queen Elizabeth appears after 1952.
Except for the penny dated 1946, all Australian pennies in this series are worth face value or somewhat more when old and in excellent condition. Here are some catalog values for all coins except as noted below:
PENNY 1938 TO 1953 (EXCEPT AS NOTED BELOW)
Apparently these tokens are 'donation receipts' issued to raise money for the up-and-coming Nazi regime in mid-to-late 1930s Germany. Translating:
ERNEUERER HEIL DEUTSCHLANDS = REVOLUTIONIZER HEALING GERMANY
ACH ICH HAB MITGEHOLFEN = OH I HAVE HELPED VICTIMS
OPFERSPENDE = SACRIFICIAL DONATION
Information about these pieces is sketchy. You cannot find them on the normal, reputable coin sites, but they appear from time to time on less-traveled historical sites and discussion forums.
Hello Bianca -- You have a silver dollar designed by a man named George Morgan, so collectors call coins like yours Morgan Dollars. They are highly prized collectibles.
Your 1901O specimen is a 'common date' coin like most of the dates and mint marks in this series. 1921 is the most common of the common dates, as there were hundreds of millions of the 1921 coins made. Coins with better dates, not common dates, are listed below. They are more valuable.
Exotic Hong Kong, now part of China, was under British authority starting in the mid 1800s all the way to 1997. As such, coins from British Hong Kong carry the reigning monarch's portait on one side.
The 1, 5, 10, 20 and some of the 50 cent denominations have the same pattern on the back of the coin. The words HONG-KONG and the denomination encircle four Chinese characters. Some 50 cent coins have four Chinese characters, but they are not at the center. Recent issues sometimes sport wavy edges. Different metals are used, including copper, 80% silver, brass, and nickel.
These coins come from Norway during the reign of Swedish King Carl XV (1859 to 1872). The one skilling coin is about twice as valuable than the 1/2 skilling:
worn: $2 US dollars approximate catalog value
average circulated: $8
well preserved: $20
fully uncirculated: $50
worn: $4 US dollars approximate catalog value
average circulated: $20
well preserved: $50