Go to your local library and find a copy of a book called Photograde. It's probably the best resource available. Failing that, you can look for the famous Red Book from Whitman Publishing. It's mostly a value guide, but has some fairly decent information about grading as well.
The 1923 Mercury dime is a common date coin, average circulated coins are $4.00-$7.00, better grade are $15.00-$30.00.
You have a Barber dime; Mercury dimes started in 1916. The value depends on its grade & mint mark, but it's worth at least $4.00 just for the silver.
A 1942 Mercury silver dime could be worth between $2.00 and $30.00 depending on its condition and grade.
If it's a U.S. dime with a date of 1944, it's a Mercury dime.
The first MERCURY dime was struck in 1916
The Mercury Dime
The Winged Liberty Head Dime also known as the Mercury Dime was minted from 1916-1946.
The U.S. Mint did not issue a Mercury Dime in 1910.
It worth about $2.00 just for the silver. All Mercury Head dimes are 90% silver. The collectible value of any coin depends on date, mintmark and grade.
The Winged Liberty, or Mercury Dime. Most people call it the Mercury Dime, but its real name is the Winged Liberty dime.
Do a Google image search for "Mercury Dime" and you will see the photo of the dime.
1936 is a very common date Mercury Head dime. Most coins of this type have seen heavy use and show a lot of wear. In general retail values for low grade coins are $3.00, better grade are $4.00. The "W" you see is on all the dimes of this series, it's the designers monogram.