Using HTML in the widget title

I need to be able to use HTML in widget title tags. I want the text color of some title words to be different than others. The way I’m doing this is using a span like this:

Widget <span>Title</span>

In the stylesheet:

.widget-title: ( color:red; )
.widget-title span ( color:blue; )

But, it’s not working since WP scrubs the title of HTML.

Can anyone suggest a solution, or tell me where the scrub is in the code? I’ve commented out a couple instances esc_html($title) in widgets.php, but no luck yet.

Thanks.