can’t remove shortcode from excerpt

Hi! I have page with nggallery shortcode like this:
[ngg_images source="galleries" container_ids="24" display_type="photocrati-nextgen_basic_thumbnails" override_thumbnail_settings="1" thumbnail_width="280" thumbnail_height="187" thumbnail_crop="1" images_per_page="20" number_of_columns="0" ajax_pagination="0" show_all_in_lightbox="0" use_imagebrowser_effect="0" show_slideshow_link="0" slideshow_link_text="[Show slideshow]" order_by="sortorder" order_direction="ASC" returns="included" maximum_entity_count="500"]

But when I try to use the_excerpt function it strip the tag until second shortcode ([Show slideshow]). So content looks like. Lorem ipsum…. ” order_by=”sortorder” order_direction=”ASC” returns=”included” maximum_entity_count=”500″] lorem impsum…

Can you please give me advice how can I strip full shortcode?

Thanks!