stripping tags from excerpt in Wordpress is not working
What you need is get_the_excerpt():
<a href='<?php the_permalink() ?>' title='<?php echo strip_tags( get_the_excerpt() ); ?>'>However, it probably won't strip out ellipses (…) since they're HTML entities, not tags.
It's because the_excerpt() outputs the excerpt right away. You want get_the_excerpt() which returns it as a string you can maninpute (http://codex.wordpress.org/Function_Reference/get_the_excerpt).
You can also use wp_filter_nohtml_kses() (http://codex.wordpress.org/Function_Reference/wp_filter_nohtml_kses)
Something like:
$title = wp_filter_nohtml_kses(get_the_excerpt());