A picture of you with the signer. Otherwise one needs a letter of authenticity.
You can buy photos at any sports memorabilia store and baseballs at any store that sells sporting goods. I get baseballs at Wal Mart and have players sign them at Red Sox Spring Training.
One can sell signed baseballs on websites like eBay, Sports Buy, Autograph Collecting, PSA Card, Geo Cities, ABC Unlimited, Richard Simpson Sports or Huggs and Scott.
The team signed baseballs from the 1940's are not as rare as you might think. Team signed baseballs fron the 1940's in excellent plus condition might be on the rare side. The players in the day signed baseball as often or more than the player today. It was part of the job of being a ballplayer. unlike the players of today they did not get paid for it. Baseballs from the early to mid 1940's sell at a lower value than the baseballs in the later 1940's. most Major League stars were off fighting in the war.
Card shows, card shops or online. Try this site (they have a lot) BuySigned.com/buysignedbaseballs
Best authentication and security.
The baseball could have been signed for a fan that only had a National League baseball on hand. The baseball could have also been signed during a World Series at a National League park where National League baseballs are the only baseballs available.
I have that same problem and yes it does. If it is signed by joe mauer and derek jeter no but if one player is a minor league player or not good then it hurts the value.
nothing....now if it was just signed by holland or just by hamilton its def. worth something....but a lot of times when baseballs are signed by multiple players it makes it less valuable