Restoring a very old leather bag

[Matryoshka]

Does anyone know much about restoring leather? To what extent can you improve the appearance of leather that has been worn through normal use? It is extremely good leather, but about 30 years old. Is it better to take it to a professional, ie shoe cobbler?

[Netix]

I know vaseline buffed into the leather does something, but I hope someone else knows more about restoring leather than I!

It wouldn't hurt to ask a cobbler.

[Phteven]

You can get shampoo and conditioner from Oroton. Or there is a US company called LovinMy Bag that sells leather care kits or accepts bags for restoration. They have some great tips on their site.
Give it a shampoo and then condition it.
You need to do a test patch first to make sure that it won't strip the colour.