Here are some examples:
if you need to remove all html tags:
#set($mystring = "<span>test span</span><p> test p</p>")
$mystring.replaceAll("</?[^>]+/?>", "");
to remove, for example, only p tags
#set($mystring = "<span>test span</span><p> test p</p>")
$mystring.replaceAll("</?p[^>]*/?>", "");
