We
seal Saltillo by dipping their finish surface before anything else -- right out of the box. They will uptake oil from your hands and stain!
I know of no way to get out
grout stains, although we have tried. I used haze and grout cleaner and it helped, but once stained, they saty that way.
Also, I cut all mine with diamond blades dry -- no wet cutting!
Efforvescence (white haze) will leech out of unsealed tiles. Phosphoric acid or vinager will take it off, but I roll it on with a paint roller, I never scrub the tile.
The
sealer I have always used -- when I can find it, is Miracle Sealer, a petroleum based siloconized product which has always left the tiles sealed and unblemished, even after they are dipped and set back into the box.
One more thing -- I never stack these tiles more than five deep. Always set them on the edges, leaning against something. Hope this helps.