I'm newbie to cryptic crosswords and I'm a bit lost as to how "abolish" is the answer to the clue "Boil rocks in wood scrap (7)."
'Boil rocks' means 'an anagram of boil' ('boil' that's been kind of jolted around).
'Wood scrap' (noun) is what you get once you've burnt some wood: 'ash'
(or maybe the author just intends 'wood', by itself, to mean 'ash' the species of tree - see comments below).
'In' means 'in the middle of'.
So it's an anagram of 'boil', in the middle of the word 'ash'.
'Scrap' (verb) is the whole thing (to 'abolish' is to 'scrap').