All my jewellery can be washed in hand hot, soapy water and dried with a soft tissue or cloth.
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 onto a hard surface, apply force or scratch the surface.
Oxidisation is a semi-permanent silver finish that will come off with prolonged rubbing through wear, silver jewellery cleaning solution, chemicals, abrasion, household chemicals e.g bleach and some perfumes.
Satin and polished silver can be cleaned by dipping the piece briefly in a jewellery cleaning solution. I use Goddards Silverdip for up to 30 seconds and then rinse.
Gold plated or vermeil pieces should only be gently rubbed with a soft jewellery polishing cloth to remove any tarnish.