If the background of of George Washington's picture is silver in a silver certificate?

Answer 1

If a bill is a silver certificate it will have those words in the banner across the top of the bill's front. The color isn't what matters, although most silver certificates from 1923 to 1957 can be identified by the use of blue ink for the seal and serial numbers.

Some private companies take ordinary bills, layer them with a tiny amount of silver or gold, and sell them at inflated prices as "collectibles". Sometimes people end up spending them after they find out they're bad investments; it causes a lot of confusion when they show up in change.