Really? I've never heard that before. I've used it on countless interior projects without issue - I do generally leave it in the workshop for a week or so to harden off though, the smell's gone by then.
I use it on internal oak projects all the time, most of my projects get at least a finishing coat in-situ as they tend to be structural.
The smell normally only lingers for a day, and pretty mild at that. I get through a lot of oil so its always fresh, its normally Rustins bought from the local shed.
Yes I always cut each coat back a little. The last 2 coats particularly, and then the final finish I give a light scuff to before waxing. I usually use a grey webrax (synthetic wire wool - like a pan scrubber), or a really old well worn piece of wet & dry paper.
I was taught when using Danish oil on a project that it would smell unpleasant if used on internal surfaces.
I was always taught to leave these unfinished or give them a couple of thin coats of shellac sanding sealer, rubbed down between coats. this would protect enough for internal surfaces, which wouldn't need as rich a finish anyway, and would smell pleasant if at all.
If you want a really nice semi gloss finish with danish oil, sand while coating it. I.e. pour your danish oil on and use sandpaper to rub it in. I did 6 coats over 6 days like this for an iroko desk and the finish is just beautiful. The smell lingered for several weeks, though. The bigger the piece, the more it smells and you want to make sure it’s warm and dry the whole time you’re working and drying the oil, otherwise it smells worse for longer. Some say it only smells when it's gone off, but not sure about that.
I wouldn't use danish oil on any place that air is trapped, particularly drawers, cupboards, boxes etc. I would finish these with something though- usually shellac or sanding sealer so that they look complete and to aid dusting. In the case of boxes I would line them with something suitable, suede or pig skin rather than flocking.
It's going to take a while to gas off (or whatever the it's called) on the inside of a closed cabinet. It needs a bit of airflow .
I've used Danish oil on a few projects but always end up wondering why, preferring Rustin's plastic coating with a briwax finish. The fumes are pretty ferocious when you're using it (vapour mask advised unless you like headaches), but it does go off reasonably quickly. Overall I don't think there's much difference in the work involved and while it isn't cheap, the big tin goes a long way.
This subject came up a couple of years ago and I chipped in with my experience of smell taking about 3 YEARS to go. See it here.
Note Phil Pascoe's wit.
Brian