Remove AddThis from feeds?

Is it possible to prevent AddThis from being added to feeds?

When I validate my feed I get the following errors:

line 1, column 38: Use of unknown namespace: http://www.addthis.com/help/api-spec
line 27, column 0: summary should not contain addthis:url attribute (5 occurrences)
line 27, column 0: summary should not contain addthis:title attribute (5 occurrences)

(I added the addthis namespace to the feed since it was not being included automatically).

http://ww.wp.xz.cn/extend/plugins/addthis/