Matt enamel can be washed in warm soapy water using a soft toothbrush to remove any dirt.
Vitreous enamel is glass and although pieces are fairly hard wearing, care should be taken not to drop, apply force or scratch the surface.
Oxidisation is a semi-permanent surface that will come off with silverdip, chemicals, abrasion or household chemicals e.g bleach.
Satin and polished silver can be cleaned by dipping the piece in a jewellery cleaning solution.
Gold plated or vermeil pieces should be gently rubbed with a jewellery polishing cloth to remove any tarnish.