carpet
I recently had new carpet installed and the installers just left the scraps in my garage. I have several that are of somewhat appreciable sizes, the smallest being 3'x5'.
I'm weighing the pros and cons of keeping it (storage space is a premium at my house), so I'm curious if it is worth keeping for partial replacement, say if a stain occurred I could cut out a square of the existing carpet and install this.
I don't know how true it is but I've heard a few times that certain plants do a good job of removing VOCs from household air. You could try investigating this claim. Here's one page that mentions it.
http://www.thedailygreen.com/going-green/tips/best-plants-for-indoor-air-quality
My wife has trouble with a variety of VOCs. It might not be an option for you to store the carpet partially outstretched in your garage until most of the odour departs.
Ignoring the fact that carpet in a bathroom is just a bad idea, I see two options:
Install a threshold to cover the gap
(source: abbey-carpets.co.uk)
You might be able to put down a new tack strip and stretch the carpet. This will really depend on how large the gap is (you didn't say)
(source: homedepot.ca)
Best Answer
Yes, a skilled flooring installer can patch in carpet to repair damage. It needs to be oriented with respect to the "grain" and pattern-matched.
Chances are you won't want to do that more than once or twice during the life of the carpet, since worn carpet tends to appear quite different from new carpet, diminishing the value of the repair. If you're a careful person you won't need to have repairs done often anyway, and if you're not you'll have too many stains to bother repairing any.
I'd only keep two or three of the largest scraps. Use the rest as utility rugs or recycle them.