Sheds demolished, most of slum too (6)
I believe the answer is:
moults
'sheds' is the definition.
(moulting is a kind of shedding)
'demolished most of slum too' is the wordplay.
'demolished' indicates an anagram.
'most of' means to remove the last letter.
'slum'+'too'='slumtoo'
'slumtoo' with its last letter removed is 'slumto'.
'slumto' with letters rearranged gives 'MOULTS'.
(Other definitions for moults that I've seen before include "Shed hair or skin prior to new growth" , "Sheds fur or feathers" , "Sheds feathers or skin" .)