Can I reset Windows ACLs for a folder?
This is easiest archived by copying the entire directory without copying the extended attributes which store the Windows ACLs.
You will need enough free space to duplicate the data, though.
Type in as root:
mv SRC_FOLDER SRC_FOLDER.bak tar -cvf - -C SRC_FOLDER.bak . | tar -C SRC_FOLDER -xpf -
After this procedure no files or directories do have any ACLs because the tar command does not copy them.