Well done swannbaker,
Apart from slag = CINDERS, we also have an anagram of
DINERS with C (CARD Head). The word suggesting the anagram is "off". A very compact clue!
Here we go if you are still up!..Umpire associated with a shock..(4) n?i? Ample unit put up with expression of dislike..(6) e???g? thanks!..then I will send it off and donate the prize to a worthy cause!!!
The answer is HAIR (check your N). So it is SHOCK in the sense of "a shock of hair". Darrell Hair is the cricketing umpire who recently accused the Pakistani team of ball tampering!