Internal Use ONLY!!  Do not be a victim! Check washing is a form of check fraud where criminals steal checks from the mail and erase the handwritten ink using common household chemicals. They then rewrite the checks to themselves for any amount they choose. The pigmented ink in the 207 Gel permanently binds itself to the paper fibers in the check, and cannot be washed off or removed! Blue Gel is waterproof, fade proof and fraud proof.  Delivery within 3-5 business days.