A quick search throws up this - "Sweating Cobs" ("sweating profusely") comes from The Black Country and the industrial West Midlands. It means sweating large globules of sweat.

Where does the phrase sweating cobs?

Heaving coal for a hungry fire / Sweating cobs to get steam higher, Of the colliers harvest that I burn / With toil and sweat, me wages earn. A cob was originally anything sort of round (like a head), so could translate as "sweating lumps". If something more specific, I'd go with Victoria's suggestion of cobblestones.

What's the meaning of sweating cobs?

Meaning: What a load of rubbish. word: Sweating cobs as in 'I'm sweating cobs 'ere' Meaning: I am sweating a lot.