Wet paint smell?
I followed Hamelman's schedule for raising a sourdough. 125% hydration, started with Rye+honey, transitioned to AP flour (KAF), been feeding twice daily (except for the first day). I keep about 300 grams of it in a sealed plastic container -- a typical dough-riser container with a sealed lid. The culture is nice and active, ripens in about 5-6 hours after feeding, and is able to raise bread and impart a pretty bold sour flavor. In the container, there is about 6-7 inches of air from the top of the culture to the lid. It usually smells vinegary / alcoholic, but no "hooch" has formed on it.
Yesterday, though, I skipped a feeding, so it sat for almost 24 hours. When I opened the container, it smelled almost exactly like wet paint, or maybe nail polish remover. I did a bit of googling around, saw another person with the same issue, he threw his starter out, for fear of poisoining, but someone else said it was OK.
If I open the container, fan it out, the "wet paint" smell goes away mostly, and it is back to the regular light vinegary smell. But it seems if the container lid is kept shut for an extended period of time, the "fumes" (whatever it is) build up inside of the container.
Is this bad? I am currently making a leaven from it this afternoon, it seems fine, but now I'm not sure if I should continue with it or not.
Should I be allowing more air to enter/escape the container? It is usually sealed completely. I can punch a couple of air-holes in the plastic lid top. I've read different people used sealed, some leave the lids ajar.
Thanks in advance for any advice.
-- Editing to add: This is a new culture almost 3 weeks old, it's only ever been in a sealed container (but there's been air in it), except for when I take the lid off for feedings (at 12 hour schedules). I've only ever used Distilled water or bottled Drinking water (Arrowhead), never tap water, and I use a clean spoon and wash my hands religiously whenever feeding it ... (even though I don't touch it, I still make sure to wash up first).