Should I Get These Coins Graded?

yes the 42 is in the same condition. I also have 10 Mercury dimes that look mint as well. I've heard it costs around $40 a coin to get them graded so I just want to make sure it will be worth it.

first off, whatever you do
DO
NOT
"WASH"
those coins.
Thats pretty much rule number 1 for beginners.

now, these look like some pretty nice coins, I especially like that half dollar.
Grading kind of seems like overkill, especially if you just plan on selling them: it costs a bit of money and will probably just eat into whatever profit you will get from selling them.
I would recommend looking up some completed ebay auctions for these exact coins to see what these are selling for. If you live in a bigger city and have any coin dealers locally they could help you get an idea of what they are worth too (dealers WILL undercut a coins value on an offer because they need to make money too, keep this in mind).
As a last resort go to a local Barnes and Nobel or Borders and look these coins up in the 2011 Red Book. This will give you some reliable information about the mintages and value of your coins, although these values can be a bit out of date (hence being the last resort)

These are some very nice looking coins, but I don't think they justify the expense of grading. But if your looking to unload, them do a bit of research with some books, get some opinions of professionals in the business if at all possible, and it will more than pay off in the end.
But if by any means these spark any interest in you as a collector, these coins would make an EXCELLENT start to a collection. CCF will be here to answer any questions you have in either case.

Forgot to say that before


You really should acquire a book or listing of some kind for values of coins. The Red Book would be a wise investment. If not, spend some time on looking up what you have. For example not only are coins worth money by their dates and condition, but some have mint errors that make them worth much, much more.
For example if you had a 1942 Mercury dime in absolutely the highest grade it would be a $30 value. IF it was what is called a 1942/41 it could go for as much as $15,000.00 in the highest grade. This is a coin with one date that appears to be on top of another date. There is one like it for the 1942D/41 also. Then too there are small and large Mint marks on the reverse too. If one of your Mercury dimes is a 1916 with a D on the back, it too could be in the upper thousands of dollars.
YOU should really get to know a little about coins before you jump in and start selling. Sort of like selling the Mona Lisa painting for ten dollars since you don't know what it is.