I take care to never get water between the scales of a carbon steel razor. If I do, I dry the area immediately and use a blast of compressed air or a hair drier to ensure that the pivot is dry and apply WD40.

Normally, I wipe my carbon steel with mineral or camellia oil for short term protection. I use a good firearms protection lubricant for long term storage.

Bathrooms have high humidity in use that can start carbon steel rusting. I heatonly the blade section below the shank under the running hot water, immediately wipe dry, then let it sit to dry on a shelf while I clean up. I then strop 30 linen, 60 latigo leather. If a carbon blade, I wipe with an oily patch and store in a coffin or pen case in my dry bedroom.

Maas on a patch or Q tip may get off early staining. Gold wash will probably not survive any abrasive and etching can be damaged. Significant rust may leave behind pits. It is far better not to let rust get started on carbon steel.

I have had no issues with my Friodur razors, SS is much more forgiving of any lapses in razor care.