Short answer is:- Yes.
longer answer:-
If you've visited the merchants site before you've used CCleaner then yes.
explanation:-
When you click on the merchants link in Quidco or Topcashback.com (TCB) it puts a cookie on your computer to attribute the sale to Quidco or TCB (and ultimately you).
The trouble is if you already visited the merchants site say a phone shop, the phone shop may have put a conflicting cookie on your computer to denote to google or another advertiser sent you there.
So to answer you question if you want to be ultra sure, it's best to use the CCleaner if you've visited the merchant site before you last used CCleaner.
If you can't remember just use it just before you click on the link in Quidco. TCB.