While reading this good page linked in the Advanced Honing section by Neil Miller (SRP member), I found this:

Sufficient aeration (supply of oxygen to the reaction site) may enhance the formation of oxide at the pitting site and thus repassivate or heal the damaged passive film (oxide) - the pit is repassivated and no pitting occurs.

Could oiling an old blade with traces of pitting be a dangerous idea if pitting is not completely under control? But how to completely passivate pitting before oiling the blade?

I usually clean old blades just with some european substitute for MAAS (and with hours and hours of work). I use sandpaper (#600-2000 grit) just in case of active rust [as in "Dealing with rust"]. I guess that in case of pitting sandpaper is not a good tool.