The chemical dictionaries define these as follows:
Sequestration
--The inhibition or prevention of normal ion behavior by combination with added materials, especially the prevention of metallic ion precipitation from solution by formation of a coordination compound with a phosphate.
--To hold (as a metallic ion) in solution especially for the purpose of suppressing undesired chemical or biological activity.

Chelation
--A chemical compound in the form of a heterocyclic ring, containing a metal ion attached by coordinate bonds to at least two nonmetal ions.
--The chemical process that takes place in chelation is complicated, but put in simple terms, the metals, bind to the chelating agent and then are eliminated.

Both definitions reference Ascorbic Acid ---- Are these both the same??

In terms of stain removal, which is better?? What is the product of choice?