Well seeing how complex recent viruses have become, the probability of removing infection from a file is very less.
So you need good knowledge regarding reverse engineering to do so. There is no AV in my experience that has done so, it woul either delete the file, or just quarantine it.
u're right..most AV's either delete or quarantine the infected file only, in some very rare instances have i come across a file being cleansed and not deleted or quarantined. it probably requires some very serious knowledge of programming to be able to do it.