Silicon or Caulk for internal sealing

Hi, do any of you diy-ers or pro's have any recommendation for what to use on internal window frames to seal off nicely where gaps have occurred or to replace failed sealant? I did this on another window last year and used caulk which once it has had the cat laid on the cill, the hair, bits of dirt just stick to it.

Need something that stays white and clean...

Ta

Silicon is almost impossible to paint over. But does the job,most UPVC fitters use silicon.

Flexible caulk could be the way forward - but keep the cat off for an hour until it skins over.

Thanks Willman. It won't be getting painted... So maybe silicon will be best?

I'd use silicone, as Caulk is prone to mould. To get a nice even bead simply apply mastic round the frame, spray with a fine mist of soapy water, squash the open end of the mastic tube, just enough for the edge to touch the sealant, run it round the frame, scraping away the excess sealant (Collects in the tube). Spray with water again and gently run your wet finger tip across sealant to smooth off any pulls or gaps. This is a great way of sealing baths, remembering to half fill it first, then apply sealant, leave to set before emptying. Always get a good smooth even bead. Hope this helps.

You need something like this; http://www.diy.com/departments/unibond-white-highly-flexible-frame-sealant/189923_BQ.prd

Its always better to use the proper stuff and you can get it in different colours to suit the frames