They just look awesome and shiny and professional.
Trumpet
the trumpet is made of brass or sometimes silver.
The player speeds up or slows down the speed of the air being blown through the trumpet.
the reason why the change has been made to the trumpet
You have probably heard somebody talk about the "last trump"? It means a trumpet. A loud trumpet is blown to herald the return of Christ.
Silver
YES you can my instructor and i have a silver trumpet and we use valve oil if you don't have oil use saliva {spit}
Brass Silver Cork Felt
No brass was not always used to make the trumpet. Gold, Silver and metal were also used.
The earliest known trumpets are silver and bronze. Some people think that earlier trumpet-like devices may have been made out of wood or other natural materials.
Most trumpets are made of brass, since silver is much more expensive. Most silver trumpet are really silver plated brass trumpets.
c.1960-1965