Short Version: I have come into possession of what I think is an older (60-70s) Rado watch. The face is in great shape but the band looks pretty worn. Would it be a bad idea to get it cleaned or should I leave it as is?

Long Version: My grandfather got this watch a while back, he died 30 years ago and my grandmother has had it since then. She died last october and I found the watch while cleaning up. I gave it to my mother (who passed a few weeks later) and I ended up with the watch. I don't feel it's worth a great deal of money, and I'm not looking to sell it but I am looking to help it maintain whatever value it has going forward (both monetary and sentimental). I'm just not sure what level of care you can give old things before you start taking away from the value.

The watch is a Rado Diastar Magic. It has what I believe are crystals for the hour markers and the logo in not printed but is on an insert. It is gold/copper looking but on the band I can see that is chipped. I think the numbers on the back of the watch say 13g-625-01.3

Any information you could give me about this watch and model would be great, as well as value and instructions for care. I can take pictures if needed and post.