It depends on their dates and denominations.
The US Treasury would exchange them for silver coins. That policy ended in the mid-1960s when silver coinage was discontinued.
That depends entirely on the country, year, denomination, and condition.
Coins struck for circulation in the US today have no silver in them.
There were no US silver dollrs minted in 1955, however, most US silver coins which were minted for circulation contained 90% silver and 10% coper.
Sorry, the US never struck any silver 1 cent coins of any date.
Coins are not usually silver these days. Since the 1960s they have been made of copper and nickel. Silver coins from before 1965 in the US were 90% silver. Foreign countries have used anything from 40% to 92.5% silver in their coins, but to my knowledge, no one has used pure (100%) silver in currency.
The US Treasury would exchange them for silver coins. That policy ended in the mid-1960s when silver coinage was discontinued.
The US Mint did not issue any silver coins of any kind in 1980. If you have silver coins dated 1980, they are not US coins.
The US didn't make any silver dollars in the 1960s.
The Balboa is the same as the US dollar. We know that US silver dollars is worth more as the Panama silver Palboa. In Panama the currency is US but there are Balboa dollar coins. Also, the silver coins in Panama are the same size as the US coins and would be worth more as the US silver coins.
That depends entirely on the country, year, denomination, and condition.
A 1985 proof contains no silver coins.
Coins struck for circulation in the US today have no silver in them.
Each denomination of US silver coins has different amounts of silver, so it's not possible to answer this question. Be more specific and post new question with the dates of the coins.
Neither the US nor Canada have struck circulating silver coins since the 1960s. If your coin is a collector's issue such as a US Prestige Proof, please post a new, separate question with more details.
There were no US silver dollrs minted in 1955, however, most US silver coins which were minted for circulation contained 90% silver and 10% coper.
None. The only US nickels that ever contained silver were made during WWII, and no circulating US coin has contained silver since the 1960s.