I bought some of this stuff recently, a quart of it:
I also had some airplane stripper which I used alongside of it, for comparison.
I must've gotten a particularly weak batch of aerosol airplane stripper (happens frequently in CA) or the paint on my '84 Univega was as tough as powder coating. Because i let that stripper sit for half a day, applying multiple foaming coats, and the paint not only failed to wipe off in sheets like it usually does, it just got "softened" a little bit. I had a drill with a wire brush and was making slight progress, but finally gave up, with about 80% of the paint remaining.
So I tried coating the frame with the citrus stuff. Used an old cardboard box in my bathroom with the fan going, and let it sit almost a day, re-coating with a brush several times in areas where the gel had thinned out.
Used a wire brush to start scraping the paint off. Really, all the citrus stuff does is soften up the paint a little, YOU do all the work with a brush scrubbing it off. But it does work, and you can (IMO) safely do it indoors. It's just a lot of work. I got most of the remaining paint off, now I need to re-coat a third time to get rid of the rest of the primer.
Personally, I prefer using full-strength chemicals outdoors, and getting the whole thing over quickly. But it's getting hard to find good chemicals that do the job, so the citrus stuff does technically work, just much slower.