Manipulated so that the body looked much older (8)
I believe the answer is:
massaged
'manipulated' is the definition.
(massaging is a kind of manipulating)
'that the body looked much older' is the wordplay.
I cannot really see how this works, but
'body' could be 'mass' (mass is a kind of body) and 'mass' is found within the answer.
'older' could be 'aged' (synonyms) and 'aged' is found in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
'so' is the link.
Can you help me to learn more?
(Other definitions for massaged that I've seen before include "Rubbed and kneaded the body" , "Provided with restorative treatment" , "Therapeutically pummelled" , "relieved tension, in a way" , "given physiotherapy?" .)