Hi samsk,
The 'c' is correct, I've just looked at the clue for it. Which is as follows.
36a) Chess champion's claim after a number of days drastically scaled down.
de(C)imated
I mated = Chess champs claim
(Dec)ember = number of days
Decimated = drastically scaled down.
The other clues are.
26a) It's ultimately scandal-mongering, say, before craft (6,5) The last letter gives Paul his S
30a) Disinterested comment about which universal rage circulates (3,3,1,4) The last letter gives the E
Could be something like - For all i care ?