The rarity of a 50-cent coin depends on various factors such as the year it was minted, the condition it is in, and any unique characteristics it may have. Some 50-cent coins may be considered rare if they were minted in limited quantities, have errors or variations, or are part of a special commemorative issue. It is recommended to consult with a coin expert or reference guide to determine the rarity of a specific 50-cent coin. **

A 20-cent coin may not be considered valuable in terms of its face value, as it is a relatively low denomination. However, the value of a 20-cent coin can vary depending on factors such as its age, rarity, condition, and demand among collectors. Some 20-cent coins may have numismatic value and be worth more than their face value to collectors. **

The 2-cent coin is considered rare because it was only minted for a short period of time in the United States. It was produced from 1864 to 1873, making it a relatively scarce coin compared to other denominations. Additionally, the 2-cent coin was not widely circulated and is not commonly found in circulation or coin collections. Therefore, it is considered rare and sought after by coin collectors. **

The 10-cent coin is known by people in the United States, where it is commonly referred to as a dime. It is also recognized by numismatists, collectors, and individuals interested in currency from around the world. Additionally, those who handle cash transactions regularly, such as cashiers and bank tellers, would be familiar with the 10-cent coin. **

The rarity of a 20-cent coin depends on various factors such as the year it was minted, its condition, and any unique characteristics it may have. Generally, 20-cent coins are not considered rare, as they are still in circulation in some countries. However, if you have a 20-cent coin that is from a limited mintage, in pristine condition, or has a minting error, it could be considered rare and valuable to collectors. It is recommended to consult with a coin expert or appraiser to determine the rarity and value of your specific 20-cent coin. **

No, a 10-cent coin cannot rust because it is typically made of a non-corrosive metal such as copper, nickel, or a combination of metals that do not rust. Rust is a form of corrosion that occurs on iron and its alloys, so coins made of non-ferrous metals like copper and nickel are not susceptible to rusting. However, these coins can still tarnish or develop a patina over time due to exposure to air and moisture. **

I'm sorry, but I do not have enough information to answer that question. If you have any specific details or context about the situation, I would be happy to help you further. **

No, cigarette vending machines typically do not accept 20-cent coins. These machines are usually designed to accept larger denominations such as quarters, dollar coins, or bills. The reason for this is to minimize the need for frequent restocking of the machine with small change and to make transactions more efficient for users. Therefore, if you only have 20-cent coins, you may need to find another way to purchase cigarettes. **