what's the difference between epsom salt and plain table salt?

Question

and could i replace epsom salt w/ table salt in a sugar scrub?

Answer 1

Epsom salt is magnesium sulfate or magnesium sulfate heptahydrate

Table salt is sodium chloride

Here is a sugar scrub that uses neither.
http://www.care2.com/channels/solutions/self/176

Answer 2

For cleaning, or for external use, yes, you can replace the one with the other.

However, epsom salt won't add (good) flavor to your food, and is not recommended for eating, unless you need a laxative.