In message <[log in to unmask]>, HISTARCH
automatic digest system <[log in to unmask]> writes
>clinkers, slag, etc.

As well as the over-fired bricks mentioned by others, there are 'small
yellow bricks from Holland' - which occur in early modern contexts from
Albany to Fort Zeeland (and many places in between).  Terence Paul Smith
'On "small yellow bricks ... from Holland"'             Construction
History 17, 31-42       2001 is a good introduction to their English
usage.  They are known as clinkers, klinkers, klinkaarts, and similar
spellings, allegedly from the goodly 'clink' they make when struck.

Best wishes to all,

Pat
(who still dreams of putting together an exhibition called "Slags!")
-- 
Pat Reynolds
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   "It might look a bit messy now, 
                    but just you come back in 500 years time" 
   (T. Pratchett)