Interior window sealant?

[jackpot]

New house, new draughts.
Most of the windows (upvc) either have no sealant around the interior. The wall is just plastered up to the frame.

Or some sort of acrylic sealant/caulk has been used that looks a mess and has cracked.

I plan on stripping the sealant and redoing.

What's the best way to strip. A sharp scraper, careful hand and elbow grease or some sort of remover.

Also what the most flexible sealant that won't crack yet paintable
Thanks

 

[Gazman16]

Just scrapers and a Stanley blade for getting it off.

I recommend this:
http://www.ebay.co.uk/itm/Wurth-SaB...t=LH_DefaultDomain_3&var=&hash=item19f9a28483

It shrinks and cracks less than most caulks. Make sure the surfaces are clean first.