Rubber erasing underside of coin at bottom of pile (7)
I believe the answer is:
masseur
'rubber' is the definition.
(someone who rubs or massages people)
'erasing underside of coin at bottom of pile' is the wordplay.
I cannot really see how this works, but
'bottom' could be 'ass' (synonyms) and 'ass' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for masseur that I've seen before include "Maybe physio" , "One easing tension" , "One kneading joints" , "Professional rubber?" , "One providing soothing treatment" .)