Toilet/Plumbing repair question

The answer may seem obvious, but/././
I was replacing the "flush arm" on an upstairs toilet when I noticed that a bit of "rusty looking" gunk had collected around the "bottom bolt" that attaches the toilet to the floor.
Asked wife (who usually cleans the darn toilets) and she said that she has cleaned similar "gunk" from around that bolt for the past several weeks.
There is no water around the base of the toilet, indicating any sort of major "wax ring" leak.
I guess my question is if I need to pull the toilet and replace the wax ring, etc. Should I just tighten the bolt on that side, or what.
I've replace wax rings before, but only when I have noticed water leaking around the base. Being that it is the second floor and a "wood" floor. I am a bit more concerned than if it was the ground floor on the concrete slab.

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