Remove Body Classes
One (untested) suggestion is to replace: unset( $classes[array_search($body_classes, $classes)] ); with $classes = array_diff( $classes, wp_parse_slug_list( $body_classes ) ); assuming the classes survive sanitize_title from wp_parse_slug_list(). It should also be alright with empty arrays. We also note that wp_parse_slug_list() is using wp_parse_list() to parse the comma separated string.