I would suggest trying it yourself, especially if you are mechanically minded and have had success at other small part disassemble/reassemble jobs. If you do decide to give it a go, I am an electronic engineer by trade and here are some suggestions that I use when I have to repair small electronic devices ...

• Have a LARGE clean, clear, flat and preferably white area available. Spend time cleaning it and if you have to, cover with a white cotton sheet.

• Break the disassemble down in to stages so you work towards one small goal at a time. Each time you reach the end of a stage spend the time to ensure everything is ready and set for the next stage.

• Have a collection of small pots available to put screws or small parts in from different stages of the disassemble. I use a collection of old 35mm film canisters as if I then have to pause during the repair I can put the lids on knowing I will not loose parts.

• Make notes on what you have done at each stage, what parts were removed, how and how many screws were involved as well as what container they are now in. You could even take photographs of each stage. This is invaluable when you come to reassemble it back and will ensure that you don't have the dreaded left over screws at the end.

• Take your time, the more you invest in to the task the greater the euphoria at the end when you have a lens that is like brand new :)

I do hope you manage to clean them up successfully as every time you take a great shot with the old lenses you will be happy knowing you have done your grandfather proud! Besides the optics in those old ones are probably pretty good glass compared to a lot of modern mass produced stuff. Good luck Evan!