While not a specialist when it comes to earthen floors, I do know a lot about linseed oil. Look for a purified/degummed/cleaned linseed oil. These terms indicate that a flax oil has been processed (there are natural and chemical methods to do so) to remove the food value in the oil so it cannot propagate mold/mildew and go rancid over time. Check the SDS and check with the supplier to confirmed it was processed naturally and includes no additives, especially solvents, heavy metals, drying agents, etc. A heated purified linseed oil should have a decent dry time and what is considered a polymerizing oil. The best options I know of are found at www.solventfreepaint.com and www.earthandflax.com. Hope this is helpful!
