I posted about a month ago asking for tips on staining a bookcase for my daughter. I've since completed the bookcase but have a question regarding the lingering stain/poly smell (oil based) I'm not sure this is the right place to ask, but I'll go ahead anyway. After finishing the bookcase I let it air out for three weeks, putting it outside in the day and bringing in at night. It's in my daughters room now and I noticed that I can still sometimes catch a scent of tge minwax. My questions are 1) after three weeks is this harmful and should I remove the bookcase and 2) is there anything additional I can do to get rid of the scent? Any input is appreciated, thanks!

In my unlearned opinion, no.

Apparently you used a combination stain and finish. The carrier of a stain (stain only) will evaporate fairly fast. Depending on temperature and humidity, probably in a couple of days. When you add the finish material, which is probably a combination of materials which Minwax won't reveal, there is no way to tell how long it will take to dry completely.

Obviously the outer surface of the finish material has dried and hardened. Now the undried finish material must make its way through the hardened upper surface and through the wood itself in order to evaporate. This will eventually happen but takes longer than one would think at first.
Depends on how sensitive you are to the odor.

Only time.

PS
How did the staining of the plugs come out. I would never use a combination stain and finish. To hard to remove if something goes wrong. I always use two separate materials. More work but gives me more control.

Plugs came out good. Sorry, I should have been more clear, I did use separate stain and poly, both minwax. Thanks for your response.

You need at least 2-3 days after staining before applying poly. Next time, try water based, particularly for inside. It now comes in a "warm" color, not crystal white. As is, nothing harmful but irritating if sensitive.