Enamel:
Enamel is glass. It is fragile. It can scratch and break as any glass would. So please handle it with care. You can dust it with a clean cloth or a towel.
Pewter:
When pewter starts to change color and starts to develop a rich patina, pewter polish or 0000 steel wool (the softest) can be used to restore its original shine. When polishing agent is used, polishing should only occur in the same direction as the original finish. Please ensure the polishing agent does not touch the enamel because it could cause micro-scratches.
Gold plated items:
Refrain from using any polishing compounds to preserve the luxurious gold layer. Even though several layers of gold have been applied on top of each other, eventually the gold layer can actually be removed by repeated polishing. Use a clean, dry cloth to clean off any unwanted stains.
Silver:
Polishing agent can be used to remove tarnish, making sure that the polishing agent does not touch any enamel in order to prevent micro-scratches.
If silver has matt/sateen finish, refrain from using polishing compounds or cloths because it will turn matt finish shiny. The more the treasure is worn, the less likely silver will tarnish. If the item is not used, keep any jewelry, including cufflinks, in original box or plastic baggie to avoid oxidation. (Krisztina, is this what you mean to convey? I wasn’t sure and edited as it thought was appropriate. Please let me know if you want to discuss.)
Murals:
They can be dusted but do not use any cleaning agent.
Mixed media:
This term describes several different kinds of media used on one piece, which includes enamel, fabric, glass beads, stains, colored pencils. No water should touch the surface!
