We have unearthed a large number of red and cream floor tiles from an old conservatory. They are 11cm square and 1cm deep and match the tiles in our forecourt, obivously laid at the time of building the house (1904). I would like to use them in our new kitchen, but am worried that they are not glazed and will stain. Can they be varnished or will I need to glaze them? Or is the project completely untenable?