Steve wrote:

Dave, and old friend of mine restores old Collins stuff,
and Ive seen plenty over the years that reek with damn
nicotene smell!

Trade secret: Ammonia and 409 kitchen cleaner! must be
done in the garage or outside, not in the house or it will
get you!

You need to be very careful when mixing common household cleaners like
that. Perhaps that was the basis for your warning. Even outside or in
a paritally enclosed area (garage with the door open) may not be enough.