The tidal range is the vertical difference between the high tide and the succeeding low tide. Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the rotation of the Earth.
Coin toning can intrinsically increase or decrease the value of coins. Natural coin toning can be quite beautiful. It can also be outrageously ugly. And because beauty is often times in the eye of the beholder, placing a value on a coin due to its toning can present problems.
1 Do not clean your coins with anything. 2  They are worth more as they are. 3  A cleaned key might as well be a cull coin. 4  If you have cleaned coins you should expect them to be devalued by at least one full grade, Brilliant Uncirculated to Almost Uncirculated or Fine to just Very Good. 5  Cleaned coins are very hard to sell.