Following the post-hike cleaning recommendations direct by conversation with Sawyer's customer service (vinegar and/or hot-water) did not clear the filter. Though Sawyer Warranty Dept asks you to package well(bubble-wrap/shock absorption inside sturdy cardboard).. If they do repair it - they return it without bubble wrap, and it'll even get loose, banging from side to side in the return box (excessive shock for a filter). You're left with a filter of unknown reliability - which if you call for replacement - they'll do nothing. Skip buying a toss and replace filter - for buying from a Company who'll send you a free filter/parts on issue, like Platypus.