Did you really try it out to remove all the Tag Types ID3v1, ID3v2, APE from the music file?
If so, then you will be left alone with the music data only.
You will not see any tag-field data in Mp3tag's dialog "Extended Tags...".
Because replaygain data are never stored in the mp3 header area (I never heard anything about this ...), there will be no extra data anymore in the music file after removing all the entire Tag Types!
Sometimes, when bad things have been going on before to the file, and different Tag Types have been stacked multiple on to each other, then the process of removing the Tag Types has to be applied repeatedly. At end Mp3tag displays an empty field in the list view column "TagRead (TagTypes)".
JJ Johnson's proposal from above does not remove the Tag Types, but only the tag-fields.
This might leave a possible bad structured Tag-Type stack as is - and the music file will stay corrupted as is.
DD.20110612.1744.CEST
Edit.
It is not correct, that I never heard about technical data in the mp3 header, read there ...
show LAME Encoder settings
DD.20110614.1111.CEST