In Arkansas’ borders, lady remains (5)
I believe the answer is:
ashes
'remains' is the definition.
(I've seen this before)
'in arkansas' borders lady' is the wordplay.
'in' means one lot of letters goes inside another.
'borders' suggests removing the centre (only the edge or border letters remain).
'lady' becomes 'she' (I've seen this in other clues).
'arkansas' with its centre removed is 'as'.
'as' going around 'she' is 'ASHES'.
(Other definitions for ashes that I've seen before include "Remnants of a fire" , "International competition" , "sporting trophy" , "Test cricket series" , "Cinders - which were once kept in the 3 20 at 18" .)