Question re: cleaning cardboard Gehrig display piece
 

In the recent LOTG auction, I bought the Gehrig Goudey stand up display exhibit. Always wanted one. Made of thick cardboard apparently. Al made the comment that it is a bit dirty and could benefit from a professional cleaning. A few questions for those who know about cleaning such items.

1. Do I need to hire a professional cleaner, or could I attempt to clean myself? If I did myself, what would I use? Or would this just be a flat out bad idea?

2. Who are the "professional cleaners" Al speaks of. How would I find a good one? I'm in the New York City area, so would have to think I could locate one if I knew what to look for.

Thanks in advance for any advice.