Removing spam referrals in Google Analytics doesn&

I set up some filters in Google Analytics to remove spam referrals. It works great for the majority of the referral links but since last week, three websites are showing up again. What's the reason for this and how to make them disappear again?

Filter 1

darodar\.com|priceg\.com|semalt\.com|buttons\-for\-website\.com|makemoneyonline\.com|blackhatworth\.com|hulfingtonpost\.com|bestwebsitesawards\.com|simple\-share\-buttons\.com

Filter 2

econom\.co|ilovevitaly\.com|ilovevitaly\.ru|humanorightswatch\.org|free\-share\-buttons\.com|buy\-cheap\-online\.info|domination\.ml|mobiletest\.me|site2\.free\-share\-buttons\.com

Filter 3

Get\-Free\-Traffic\-Now\.com|googlsucks\.com|theguardlan\.com|quirktools\.com|guardlink\.org|site3\.free\-share\-buttons\.com|site4\.free\-share\-buttons\.com

Filter 4

Site5\.free\-share\-buttons\.com|site6\.free\-share\-buttons\.com|event\-tracking\.com|free\-social\-buttons\.com

The following three referrers show up again in Google Analytics.

www.Get-Free-Traffic-Now.com (Filter 3)
free-social-buttons.com (Filter 4)
www.event-tracking.com (Filter 4)

EDIT:

Someone marked this as a possible duplicate of this question but that's not correct. The answer there suggests using filters but that's exactly what I've been doing for the last couple of months. Someone else suggested looking for fake hostnames but I only see the valid one so nothing to block there.

The method I found the best was to use custom dimension as the filter.

The "spam" is not spam on your page, it's only your GA-code that is used on a different page.
Since the "spam" is never on your page they can't know what dimension or how to use it.
So..

In your Javascript code add a dimension like:

<script>
   (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
   (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
   m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
   })(window,document,'script','//www.google-analytics.com/analytics.js','ga');

   ga('create', XXXXXXX, 'auto');
   ga('send', 'pageview', {
      'dimension1':  'true'
   });

</script>

This sends a custom dimension with the value "true". In Analytics you add it to the Custom Definitions -> Custom Dimensions.

Then in filtering you INCLUDE on this custom dimension if it contains "true" value.
So only data with a Custom Dimension1 with value "true" is counted. If the spammers finds this out.
Then they are good :-)

This way you will only get true data on Google Analytics and no strange referals.
I have had this running for about a year on my page now and have no strange referals anymore.
All referals I have in GA is true referals.