Hello Khaja,.. my technique/suggestion is.. wash-rinse-repeat... until it is clean.
..that is,.. import, repair, export (as parasolid (native format).. import, repair, export,.. until it's a squeaky clean parasolid solid or surface.
Locate the problem areas. Then split the part locally around those areas. Export the part into individual pieces split into zones with & without problems. Import & fix the problem sections then merge after surface have been healed.
Sample: (splitting up the body speeds up healing since you work in much smaller files)