The historic common law principle of salvage (infra) which prohibited the payment of any salvage reward where the salvage operations had been unsuccessful. "No cure no pay" contrasts with the historic civilian concept of "assistance" (supra), which permitted the payment of salvage remuneration even if no successful result was ac [..]

No cure no pay is a form of salvage contract in which the salvor receives no payment if s/he fails to save any property. The payment will be made under this scheme only if the party makes a successful claim.

You give the sample to the customer.. If they are satisfied with the quality and use it, then you invoice.. If product failed you don't invoice..