That Yale lock is a push key pin tumbler lock. That style was made from the late 1800’s to 1926.After 1926 it had Yale on both sides and was made up into the 1950’s. I just made a key for one of those exactly like yours yesterday. It can take a little time as you first have to pick the lock open, then dissassemble it, then cut a key to the pin configuration. The lock with a origional key is only worth around $30 - $45, so having a locksmith do the work wouldn’t be worth the money. Me on the other hand, I like to tinker with my own old locks and enjoy picking the old ones open and making keys for them. as far as cleaning goes, I usually spray them down with a good penetrant oil and scrub them clean with an old tooth brush or brass hobby brush, then I coat them with aerosol gun oil. Good luck, Mark🙁y):
