CTFclock clearly refers to ctftime.org
Scrubbing implies that it was trying to be removed so we want to look at the wayback machine
Putting the event URL into wayback machine gives 3, really 2, reaults.
The result in March has the string a5abef5222adc680a453607384bcb4d2 in it, which is the text for the flag
DUCTF{a5abef5222adc680a453607384bcb4d2}