So I did a quick scan and it's not that great. I like the idea of a light table. Guess it's my next investment.
You don't have to buy anything special to make a light box, a sheet of plexiglas or glass (careful of breakage), lay a (thin) sheet of clean white paper over the glass place the note on top of the paper. darken the room, turn off other light sources, project lamp light from below the glass (behind the note) and take some photos. some light tables can get expensive and unless you are going to be shooting like this a lot or need the light table for something else the expense may not be worth it to you.
Some scanners come with basic editing tools, maybe you can 'crop' the note and resize the file to 600 pixels on the longest edge, then upload. Also if you can scan the note at 300 dpi that will help with image quality. Here's a test example for you that I did with Photoshop from your file, this one isn't as big as it could be but you get the idea of getting rid of the excess background from the scanner: This one was resized to 1600 pixels wide:
Not wear, but light. The old inks used in fountain pens weren't very lightfast. Sometimes you'll even see an uncirculated note with signatures that are nearly gone.... When the signatures were stamped or lithographed instead of being hand-signed, they tended to last longer--but it was mostly the larger banks that bothered with such things.