My wife and I are renovating a mid-1800s Italian Villa, trying to bring it back from a four-unit dwelling to single family, and being sensitive to the history and period.
Most of the original floors, under as many as six layers of carpet, vinyl, linoleum, etc. are tongue and groove pine. It appears as if the boards were not close when installed and that someone at one time used putty to close the gaps, which are between each board, and often as much as a quarter inch wide.
Especially in places like the kitchen, we don't want the grunge of daily life accumulating in the cracks. I've been looking for a putty or filler that I could use, available in relatively large quantity, to fill the gaps. While it's not my ideal, it seems to make sense. We would need a dark color, to complement the color of the floor when sanded . . .