How can I identify this unusual antique wood finish smell?

Question

I recently purchased an antique oil painting (18th century), whose frame has a very particular smell that I had never smelled before, touching the frame imparted a fair degree of grime onto my hands, but the smell is not like any grime I've smelled before. It's a very unusual smell that I can hardly describe, it's pungent, however not entirely unpleasant. I wouldn't want to be subjected to the smell continuously, but a rare whiff of it is pleasingly unique.

A cursory google search seems to want to tell me that this is simple "antique mildew", but I wouldn't describe the smell as mildewy or really even associate it with decay rather than age. It seems like a rather inert smell, seemingly not too noxious to breathe, but ingesting something that smelled like this would surely give you a stomach-ache or worse. It's not quite "sour" (but almost) or "chemical", but if you told me it was a wood finish that had long ago "turned" or oxidized, I would not be surprised. However I am not familiar with the normal scents of most wood stains and finishes, let alone antique ones.

I was content to let this mystery lie, as I didn't feel it necessary to mitigate or remove the smell of the painting (it is a part of the painting's patina, after all), but a few weeks later I purchased a vintage (possibly antique) wooden mortise gauge for woodworking, and it had the exact same smell, but much stronger, the gauge is basically the same shade of darkish brown wood stain, but as I'll be using it with my hands I wanted to clean it off, whatever it may be. Especially as the smell will linger on the hands until a vigorous scrubbing. And the gauge doesn't seem to slide as well as would be expected, possibly due to this grime building up.

I'm sure to remove it I could just try increasingly rough cleaners, and at worst sand and refinish the gauge. But more than anything I'd enjoy precisely identifying the smell. I realize identifying smells on the internet is difficult, but as the next outlet for identification is shoving pungent antiques under the noses of people more learned than myself, I figured I'd try the internet first.

Answer 1

So this could be some sort of lacquer thinner or a de-waxer like xylene. They both can have a slightly pleasant sweet odor that is quite powerful even in minute amounts.

Often times the original finish on these old things is desirable so people tend towards NOT using strippers but rather use e.g. Butcher's Wax which is a sealing wax product that dries slightly cloudy but is clear when thin and buffed. This wax is fairly neutral and commonly used as a finishing wax for antique frames (gilt or otherwise). It is also useful for lifting dust from cracks and crevices. Gilt finishes mostly wash up (read: are removed) with water, so a wax product avoids damaging the gold. As a sealing wax, it also protects wood and it can be tinted.

Butchers Wax also has a somewhat sweet odor and if it is not thin and buffed, or is not dried can feel like grime. If used on a particularly dirty object it might have the tactile features you describe.

Answer 2

Per https://www.woodshopnews.com/columns-blogs/choices-limited-by-availability-for-an-early-american-craftsman

In the 18th century there were only three large categories of finishes available: oil, which almost always meant linseed oil; wax, which almost always meant beeswax; and varnish.

It is very unlikely that you would smell the same thing in a new finish. Manufacturers can change the recipes of their products in just a span of 10 years, let alone 200-300 years.

The age of the finish and the environment it was stored in are likely culprits of whatever smell you are experiencing.