Search:

I can kind of understand it, kind of like the smell of WD40 myself.

Tussock here is your AR-15 Extractor retainer pin size:

OAL: 0.446" (=11.33mm)
Diameter: 0.099" (=2.51mm)

Source: Colt AR-15 Pin Sizes

Methinks a re-purposed 2.5mm drill bit...

I use a razor, but no cream, just water. Works a treat, especially under the shower.

Do the degrease and the vinegar. Will eat only the rust - unless you leave it soaking in it for days or forget it all over again of course (-:

Degrease it with alcohol or acetone, then soak overnight in vinegar.