if you want to perform a classical histological staining procedure for Nissl (Thionin or cresyl violet acetate) you do not need to strip the fluorescent antibodies. Because light microscopy would not interfere with the fluorescent conjugates.
However, in the case you want to perform a fluorescent Nissl staining, then I have no idea how to strip the fluorescent conjugates.
if you want to perform a classical histological staining procedure for Nissl (Thionin or cresyl violet acetate) you do not need to strip the fluorescent antibodies. Because light microscopy would not interfere with the fluorescent conjugates.
However, in the case you want to perform a fluorescent Nissl staining, then I have no idea how to strip the fluorescent conjugates.
If you are doing a histological stain then you do not need to strip fluorescence (see Stefan's comment). If you are doing a second fluorescent stain then you could easily just use a different fluorophore (i.e. if you stained with AF 546 previously, then just re-stain using AF488 or AF 647 etc.). If you really need to strip the fluorescence (and your sections are well adhered i.e. fixed tissue on a charged slide) then simply perform antigen retrieval heating the tissue to 95-99 degrees in water bath in Sodium Citrate (10Mm) pH 8 for 30 minutes (which will strip your Ab) and then re-stain.