Batman dons a special suit just for fighting Clayface, equipped with lots of spray to use against Basil Karlo’s mud. And when Clayface touches Batman’s face, absorbing his DNA and revealing his secret identity to Jim Gordon and some Gotham cops, Batman shows his preparedness by taking off a plastic fiber mask from his face, preserving his secret identity.
Funny to see them fighting when in a few issues down the line, Batman would recruit Clayface to join his Gotham Knights.
From – Batman Vol. 2 #20