Some remember that collar (6)
I believe the answer is:
bertha
'collar' is the definition.
(I've seen this before)
'some remember that' is the wordplay.
'some' indicates a hidden word (some parts of the word are used).
'BERTHA' is hidden in the letters of 'remember that'.
(Other definitions for bertha that I've seen before include "Big - - , WW1 gun" , "Big ..., heavy German howitzer in World War 1" , "Female name; Big -, World War one German howitzer" , "Girl's name - big German WWI gun" , "Big girl" .)