The Apollo 11 medal was part of a Franklin Mint series called "The National Commemorative Society;" the medals were issued from 1964-1976. Each of the 0.925 fine silver (i.e., sterling silver) medals contains 0.83 troy ounces of fine silver. At today's silver spot price of roughly $16.75 per ounce, your medal contains about $13.90 of silver. If you try to sell it to a coin dealer or gold/silver buyer, you will likely be offered 50-80% of this amount - $7 to $11 (maybe even less).
The Jimmy Carter "Eyewitness" medal was also part of an ongoing series, but the pieces were sold individually to members of the Franklin Mint Collectors Society. I believe your medal has 0.70 troy ounces of fine silver, which puts its melt value (today) at about $11.75. Again, dealers will offer much less.
If your goal is to sell them, you would likely do best to sell them to another collector via a site such as
ebay. A collector interested in the pieces for his/her collection will generally pay more than a dealer who will likely turn them over to a refiner be melted.
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