Plugin removal still leaves the tracking code, how can I remove this?

I have deleted the Plugin and it has been removed from the Plugin folder. When I view the home page code it is still inserting two lines of code.

<link rel=’dns-prefetch’ href=’//platform-api.sharethis.com’ />

<script type=’text/javascript’ defer=’defer’ src=’//platform-api.sharethis.com/js/sharethis.js#product=ga’></script>

When I check with GTMatrix they report this is affecting my sites performance.

I have reported this to Plugin supplier, but they have not yet provided a solution.

So it seems anybody that has tried the Plugin is still providing website tracking