The Collaborative International Dictionary of English v.0.48:

Clam \Clam\ (cl[a^]m), v. t. [imp. & p. p. Clammed; p. pr. &
   vb. n. Clamming.] [Cf. AS. cl[ae]man to clam, smear; akin
   to Icel. kleima to smear, OHG. kleimjan, chleimen, to defile,
   or E. clammy.]
   To clog, as with glutinous or viscous matter.
   [1913 Webster]

         A swarm of wasps got into a honey pot, and there they
         cloyed and clammed Themselves till there was no getting
         out again.                               --L'Estrange.
   [1913 Webster]