Porcelain Enamel, Corian, Plastic/Formica, Silestone
CANNOT be kashered (for Pesach). Clean and cover for cold food. Cardboard or thick pad for hot food and utensils.
Granite, Marble, or Stainless Steel
Can be kashered by doing eruy roschim (purging through a hot water pour). Make sure that the material is a PURE granite, limestone, etc. Sometimes they are really “composites” which have plastic in them and therefore CANNOT be kashered.