I have had best luck with Circa 1850 "Heavy Body Paint and Varnish Remover" - can not really comment about odour - I work in garage, not in house. I have had multiple used rifles with stocks that somebody sanded or scraped - don't do that!!! Butt plates, other metal no longer fit because wood was removed - wavy where it should be dead flat - rounded corners that should be square - square corners that should be rounded. Just nasty to take sandpaper or scraper to wood to remove finish!!!
Depending on the stock, a rough terry rag liberally sopped with acetone works well to then try to scrub out any oils that were in the wood, underneath the old finish - or in the barrel channel, in the magazine well, or under the butt plate where finish was often not applied, but oils found their way in there. Is a bleaching product - oxalic acid - works great to pull any stains from wood caused by rusting iron - is the active ingredient in "BarKeepers Friend" - but leaves wood cleaned, but bleached looking - usually needs some staining to cover that.
A bit of Red Mahogany Minwax oil stain mixed with boiled linseed oil - 50/50 is pretty strong - works very nicely as first coating to even out various bruises and old mis-colours on elderly walnut. Most that I have done have then received multiple very thin Boiled Linseed Oil - very thin - like two or three drops rubbing in with fingers and palm - dip finger tip into container of linseed oil - that is enough for an entire stock's coating. Normally is dry to the touch in 6 or 8 hours - ready for another very thin coating. Repeat until totally bored with it - 5, 10, 25 coats. Others may prefer something more shiny - follow that product's instructions, I guess.