Clag

The sky was thick with dirty gray clag

This programme included practice interceptions, simulator training, day flying, night flying, clag flying -- in addition to […] [a footnote states that clag flying was Air Force slang for foul weather flying.]

We went along in the clag for what seemed like an eternity [a footnote defines clag as low cloud cover]

He ran wide in the corner, hit the clag and spun off.

As when the orchard boughes are clag'd with fruite

Can such draw to me/My stund affections all with Cinders clag'd

Wash the rice well in two waters, if you don't wash 'em, 'e will clag [clag means get sticky] and put 'em in a pot of well-salted boiling water.