Rings up to gas about everything (5)
I believe the answer is:
calls
'rings up' is the definition.
(I've seen this in another clue)
'gas about everything' is the wordplay.
'gas' becomes 'cs' (short for 2-chlorobenzalmalononitrile).
'about' is an insertion indicator.
'everything' becomes 'all' (all things).
'cs' going around 'all' is 'CALLS'.
'to' acts as a link.
(Other definitions for calls that I've seen before include "Makes a social visit" , "Speaks to attract someone's attention" , "Pays a visit" , "Names" , "Shouts" .)