So let me come to the main part of this post.
Just rename the file extension with some other name, as simple as that right.
If I have a audio file: one.m4a
Then rename the file as : one.a4m
Use ES file explorer to rename batch of files.
Rename the extension in reverse order of the original extension so that you won’t mess up while renaming it to original format. You no need to remember which format this file belongs to.