mold, rot or what?


have a room with large 60-yr old window w/wood trim . have another window (15 yrs) in same room w/white non-wood trim. began using a humidifier in room - hygrometer says 45% rel hum.
this week while cleaning, saw little spots of blackish mold growing along the bottom edge of the white non-wood trim window. assuming it's due to the condensation that falls from the window. not a whole lot - got some vinegar, sprayed, wiped clean, no problem.
took a look at the other window (old wooden one) and where the glass meets the wood, there's a large streak of this black stuff on the wood. took a paper towel with some vinegar (i know i probably shouldn't), wiped it along the wood and ALOT of black stuff came onto the towel. odd thing is the stuff doesn't look like the typical circular mold colonies.
what is it? typical of mold? mildew? or does wood rot like that? or could the locks/handles be causing problems? even after wiping it a million times, wood still looks black - like someone ran their finger in black shoe polish and rubbed it into the wood.
getting windows replaced this summer, but sinuses need the humidifier now (dry cold winter).
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snipped-for-privacy@gmail.com wrote:

When there is nothing to seal off the gap between wood and glass, condensation will seep down into the wood. Usual on the inside of window is to apply the finish - varnish or paint - of the frame in a fine line onto the glass to seal this off. Wipe it with bleach/water. Wood that is wet for a while will sometimes take on a black stain that is almost impossible to remove. Rust remover might help, as well. Don't mix with anything else.
The more moisture that gets down into wood frame, the more finish will crack and peel. But you know that already. FWIW, mildew is mold and it will grow just about anywhere it is damp enough and finds some good organic food, like cellulose. I don't think circular colonies are typical unless they are growing on a slice of bread.
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snipped-for-privacy@gmail.com wrote:

I would suggest reducing the setting on the humidifier now to reduce the problem until you can get better windows less subject to condensation at the higher levels. When it is extra cold you will need to reduce the humidity and you will be able to up it again as it warms up a little.
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Joseph Meehan

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