The module ContigSanitizer removes "bald spots", or regions of zero read coverage, from the contigs in an assembly. If a contig has an internal "bald spot", it will be split into smaller contigs. ContigSanitizer relies on the function ContigSanitize in the AssemblyOps module.
Because read-to-contig alignments are described by ReadLocation objects, any assembly module that modifies or removes ReadLocations may inadvertently create "bald spots". Such modules include VacuumLocs and FixLocations. In module pipelines, it is common to run ContigSanitizer shortly after running these modules.