How to clean rust on objective lens

[flyingmelon]

I have an old microscope. Which has some rust on the edge of the objective lens surface. I know acid can clean it, but that will damage the mount. Any good idea for this? Objective lens should be made by quartz glass.

[Darby]

Can you physically get at it? Most "scrubby" pads (plastic, not steel wool) should be able to scrape rust without hurting the glass.

[canalon]

would not try scrubbing in case the glass is coated with something that could get scratched. Oil or something like WD40 immediately followed by thorough cleaning with isopropanol (or ethanol or any lenses cleaning solution) would be my bet