A car that's made of glass? (3,3)
I believe the answer is:
jam jar
'a car that's made' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.
'glass?' is the wordplay.
I cannot really understand how this works, but
'glass?' could be 'jar' (I have seen 'Glass of beer ' mean 'jar' so perhaps 'glass' could also mean 'jar') and 'jar' is found in the answer.
The remaining letters 'jam' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'of' is the link.
Can you help me to learn more?
(Other definitions for jam jar that I've seen before include "Container for conserve" , "Container for preserve" .)