Show a long wire element, such as you might find in a toaster. Hold it between your hands and the wire begins to glow! It continues to get hotter and hotter until it appears to be RED HOT!
To cool it off, simply "blow on the wire"!
There are a million uses for this prop. Use it as a novel card location, where the selected card is found with a big scorch mark on its face; a couple of pieces of bread are shown, then magically become TOASTED!!
Many ideas are included in the manuscript which comes with the wire.
NO electricity; NO batteries; NO chemicals - just magic! Easy to do.