Regularly pass up rest to get the black stuff (7)
I believe the answer is:
asphalt
'black stuff' is the definition.
'asphalt' can be an answer for 'stuff' (asphalt is a kind of stuff). I am not sure about the 'black' bit.
'regularly pass up rest to get the' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
'rest' becomes 'hal' (I am not sure about this - if you are sure you should believe this answer much more).
'to get' is a charade indicator (letters next to each other).
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'pass'+'up'='passup'
The alternate letters of 'passup' are 'asp'.
'asp'+'hal'+'t'='ASPHALT'
Can you help me to learn more?
(Other definitions for asphalt that I've seen before include "Paving material" , "Roofers use this" , "Bituminous material for roofing, paths etc" , "Mixture of tar and gravel for paving" , "Mixture of tar and gravel used in road surfaces" .)