How on earth do I clean this windowsill?

[ohfook]

Just moved house and for the most part I'm happy with it.

I love to get as much light into the house as possible, but what we didn't notice on viewing is the state of the windowsills- you don't notice it if the blinds are down.

Basically they're filthy but the filths appears to be stuck on some sort of uneven textured adhesive that runs along it.

If anyone can tell me how to get it off without actually needing to buy new windowsills, I'd be very grateful.

Cleaning spray and a toothbrush should get into all the nooks and crannies

bleach spray or the mould spray for bathrooms, either will work. Just leave it to sit for an hour

Looks like someone's been a little enthusiastic with the caulk/mastic gun. You can probably scrape off most of the excess on the top surfaces. I find cleaning with meths gets rid of lots of sticky substances

Looks like it's penetrated smeared silicone, I'd be stripping it all off.

It shouldnt really need any silicone inside the frame, worth looking into why it's there..

You can get UPVC cleaner for the bottom of the windows. The filler stuff is probably going to need sanding and painting rather than cleaning.

Toothbrush and soapy water, bit of baby’s sterilising fluid

@FixTheBone

Looks like it's penetrated smeared silicone, I'd be stripping it all off.

It shouldnt really need any silicone inside the frame, worth looking into why it's there..

And this!

It's quite normal to apply silicone or caulk to the edges of older windows at least - doesn't indicate any issue ime, but yes that is the problem. You need to scrape out the old silicone and apply new stuff, making sure not to smear it over the flat surfaces as this has been. Having recently done this job myself I can highly recommend getting a proper silicone remover/shaper tool from somewhere like screw fix. Makes a night mare job into a relatively simple one.

Agree with above pp it's excess mastic. The Pink Stuff Paste will get the majority of the mould off but ideally I'd scrape off the mastic, clean and reapply.