- preg_replace: documentation ( source)
<?php
$page = <<<PAGE
Valora-shop.ru: <a href="http://www.valora-shop.ru/cat161.html" target="_blank">кассетный нагреватель для воска</a>, воскоплавы для депиляции. </sape_noindex><!-- <sape_debug_info>czoyMToiU0FQRV9DbGllbnQgUEhQIDEuMi4xIjs=</sape_debug_info> --><!-- <sape_debug_info>TzoxMToiU0FQRV9jbGllbnQiOjM0OntzOjE/+2OiJfbGlua3NfZGVsaW1pUoZSx0KX0/pKCkKLy8tLT4KPC9zY3JpcHQ+Ijt9</sape_debug_info> --></h6>
</td></tr></table><table width="250" border="0" cellspacing="0" cellpadding="2">
<tr>
<td width="250" align="center" valign="middle">
<!-- <sape_debug_info>czoyMToiU0FQRV9DbGllbnQgUEhQIDEuMi4xIjs=</sape_debug_info> -->
PAGE;
$page = preg_replace('/<\!-- <sape_debug_info>[^\<\>]*?\<\/sape_debug_info\> -->/gmi', '', $page);
echo $page;