 After the initial rejection of his patent, Scoggin drafted claims more carefully to distinguish the prior art, limiting new claims to the use of a rib seal, rather than a washer or gasket, to maintain a seal, as well as the existence of a small space between the overcap and the sprayer.Clark held that because Scoggin narrowed his claims to meet the limitations requested by the patent examiner, Cook Chemical could not now claim broader subject matter (see Prosecution history estoppel).Clark further held that the differences between Scoggin's design and the prior art were simply too minor and non-technical to maintain the validity of Cook's patent.