VBA code contained in Module Streams is made up of compiled code (PerformanceCache) and source code (CompressedSourceCode).
VBA stomping consist in altering or suppressing CompressedSourceCode and leaving the PerformanceCache unchanged:
As you can imagine, it must also be possible to change the PerformanceCache and leaving CompressedSourceCode unchanged:
Suppressing the PerformanceCache is a technique that I call VBA Purging:
More details can be found in a blog post I wrote here.