Easton's Bible Dictionary: M. G. Easton, M.A., D.D.
The leather of shields required oiling (2 Sam. 1:21; Isa. 21:5), so as to prevent its being injured by moisture. Copper (= "brass") shields were also in use (1 Sam. 17:6; 1 Ki. 14:27). Those spoken of in 1 Ki. 10:16, etc.; 14:26, were probably of massive metal.
The shields David had taken from his enemies were suspended in the temple as mementoes (2 Ki. 11:10).