how do you fix window mastic?

[Haroldwilson]

My window is minging. What can I do to sort it out? There doesn't seem to be anything wrong with the unit itself so don't want to replace, is it possible to take out the minging mastic somehow and replace?

That is an abomination. Even without the black stuff.

You can normally scrape it all out, just be careful not to cut or scratch the underlying plastic, wooden or plastic scrapers are probably best. You might find cutting the surface gently with a knife and then freeing an end will allow you to peel the whole lot off.

Start on a small bit first to test out your skills.

Thank you @GasPanic And then just reapply mastic? Silicone?