Before being used the clay must be thoroughly broken up and puddled to make sure that there are no lumps left, and that it will work easily.
(no lumps; left; ) (the clay; must be thoroughly broken up; T:Before being used) (it; will work easily; ) (the clay; puddled; T:Before being used)
no lumps the clay it the clay
left must be thoroughly broken up will work easily puddled
T:Before being used
T:Before being used