Edit .htaccess on plugin deactivate - .htaccess

Question

I am trying to add rewrite rules in .htaccess during plugin activation. How can I edit/roll-back rewrite rules in .htaccess on plugin deactivation?
function add_to_htaccess( $rules ) {
$content = <<<EOD
\nAddOutputFilterByType DEFLATE text/plain
AddOutputFilterByType DEFLATE text/html
AddOutputFilterByType DEFLATE text/xml
AddOutputFilterByType DEFLATE text/css
AddOutputFilterByType DEFLATE application/xml
AddOutputFilterByType DEFLATE application/xhtml+xml
AddOutputFilterByType DEFLATE application/rss+xml
AddOutputFilterByType DEFLATE application/javascript
AddOutputFilterByType DEFLATE application/x-javascript
AddOutputFilterByType DEFLATE application/x-httpd-php
AddOutputFilterByType DEFLATE application/x-httpd-fastphp
AddOutputFilterByType DEFLATE image/svg+xml
SetOutputFilter DEFLATE\n\n
EOD;
return $content . $rules;
}
add_filter('mod_rewrite_rules', 'add_to_htaccess');
function myplugin_enable_flush_rules() {
global $wp_rewrite;
$wp_rewrite->flush_rules();
}
register_activation_hook( __FILE__, 'myplugin_enable_flush_rules' );
The above function adds rewrite rules with in default WordPress rules lies between # BEGIN WordPress and # END WordPress. What could I do to add it separately (at the bottom of .htaccess ?)

Answer 1

I have managed to do this at my own. Below is the function I have added.
function myplugin_deactivate() {
// This will remove the rewrite rules
remove_filter('mod_rewrite_rules', 'add_to_htaccess');
global $wp_rewrite;
// Flush the rewrite rules
$wp_rewrite->flush_rules();
}
register_deactivation_hook( __FILE__, 'myplugin_deactivate' );