how can i do precepitate silver in plastic
There's more than one way, but one common method is to use the Brashear process (this is the same process used for silvering glass mirrors, and it is non-electric). A step-by-step set of instructions for the method is found at the first link below. For plastics, it may be necessary to sensitize the surface before trying to deposit the silver. There are a number of ways to do this, and one is discussed at the second link below. See if your library has books on metal finishing. These contain detailed instructions for these processes and much more.
