Coroded button shafts

I pulled my old Ikelite housing for my Nikon D70 out of mothballs last week so I could use the D70 while I'm waiting for Ikelite to service my D300 housing (due to issues with a leaking sub-command dial control). Some of the push-button controls were a little sticky so I removed each one and gave them and the O rings a lube.

While I had them out, I noticed that some of the shafts had corrosion on them. I don't believe the corrosion is far enough down the shaft that it would reach the O ring but I tested the housing (sans camera) yesterday at 11 metres and it didn't leak at all after using control multiple times.

Once I get the D300 housing back, I'll probably give the D70 housing a good clean so I can continue to use it as a backup. Do you think I can just clean the corrosion off with steel wool or would I be better off replacing with new buttons? Would cleaning the corrosion off reduce the snugness of the shafts in the O rings?

I'm sure I can get Ikelite to ship some buttons and O rings back with the D300 housing.

Why risk it - replace them.

Is it corrosion (as in brown stain...) or could it be calcium (whitey stain...). If it is the first, I would not risk it. If it is the second I would submerge the buttons in vinegar for a couple of hours and then wash them with fresh water; they usually get cleaned and look like new...