Before doing any spell ritual for a example doing a reversible spell , should you take a protection bath and spell to cleanse yourself after doing this or it’s not needed ? Or what should be done after doing negative work?
I don’t consider a reversal spell to be negative work, but I don’t think it’s ever a bad idea to do protections and cleansing before a working. You can do it after, too, especially if you’re doing baneful magic.
I don’t know that reversal spells are baneful magic either. I would cleanse yourself & your space before doing any spell work though & cast a circle if it would make you feel better. 
Thank you 