It would work, I wouldn't recommend anything scented though, as it may cause problems. Also, quick warning to be careful while drying, I'd say put the dryer on low or...
Copper sheets previously used in solar cells can be melted down and stripped of impurities, to form high-grade copper as a product, but this would require lab equipment.
Yes. Natural amber in most cases floats in salty water and sinks in fresh water. This is how in some places, for example the Baltic Coast, you can find it...