Spirit of the alteration in a manuscript (5)
I believe the answer is:
meths
'spirit' is the definition.
(I've seen this before)
'the alteration in a manuscript' is the wordplay.
I cannot really understand how this works, but
an anagram of 'the' is 'eth' which is within the answer.
'manuscript' could be 'ms' (abbreviation for manuscript) and 'ms' is located in the leftover letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
'of' is the link.
Can you help me to learn more?
(Other definitions for meths that I've seen before include "Methylated spirits (colloq.)" , "Violet-coloured alcohol" , "Fuel" , "Spirit" , "unsuitable alcohol" .)