Regardless of the original contract, it's entirely appropriate for a vendor to tell the customer how to use any materials.
Imagine a _leaded_ pipe supplier not being allowed to tell the department of war they shouldn't use leaded pipes for drinking water! It's the job of the vendor to tell the customer appropriate usage.
Imagine a _leaded_ pipe supplier not being allowed to tell the department of war they shouldn't use leaded pipes for drinking water! It's the job of the vendor to tell the customer appropriate usage.