Do the MLB pro players sign autographs before or after the exhib. games?

Yes, before and after. I've been collecting autographs for years but never been to Spring Training. However, I know plenty of people who have and can tell you a few things.

First of all, players even sign before MLB games. So in the relaxed atmosphere of spring training it is much easier to get them. Get there when the stadium opens and wait by player entrances. You can get them in the parking lot or as they are leaving the stadium. I hear that practices and after the games in the parking lot are the best places, practices being better. Get them on their way out or in, not when they are warming up. Don't yell out to them during practices unless you are young because they will not come over. Also, that is their warm up time so you need to wait until after they are finished with their business. If you are going to stay after the game then you might be there for a while so be prepared to wait. Look for the player exit since that is where the players will be coming out of. If you can't find it then look for the other people who will be looking for signatures. Again, you might have to wait though.

Of course you can bring your camera to the game, as long as you don't try to sell a copy of it.

For making the signatures last the longest use a blue sharpie on photos or cards, and a blue ball point pen on balls. If the ball isn't leather (if it is plastic), don't use a pen. You are better off using a sharpie at that point.

As for those teams, I know that Jason Kubel, Chase Headley, Kyle Blanks, Daniel Hudson, Adam Eaton and a few others are very good signers. Younger players/prospects are also more likley to sign.

Hope this helped, good luck!

when ever they can but more after the game

they do both but prefer to do it after