Can You Recommend A Specific Silver Test Kit?

Never used these before but have heard good things. They have a bunch of different ones for all sorts of coins.

http://www.fisch.co.za/home.htm

Option 1:
Find a friend with a decent metal detector.

Silver and copper coins register at the highest levels, because they are the highest conductors.
If I turn mine to "10", the only thing that will sound is copper or silver.
I can even discriminate modern copper plated pennies with confidence.

Option 2:
Heat the coins up with an induction heater.
Use a FLIR camera to view the coins, the silver coins will look different then other metals, at the same induced temperature.
You would have to build this rig and don't melt your coins!

Neither of these will tell you an accurate purity.
Example, a 95% copper coin sounds pretty much the same as a 98% copper coin with a my metal detector.

if you are really worried, sell the coins and buy from some place that doesn't make you nervous.

Males me wonder what the Lone Ranger did to check for Purity for his Silver Bullets. And in the movies or books on Warewoves, it is never clear as to the required purity of Silver in Bullets to kill a warewolf.
This would indicate there is a sure method for checking Silver Purities.