My client's new website is example.com, the old website is example.co.uk. I've re-pointed the A Records to the new website (so as to leave the emails alone) and put in 301 redirects from old pages to new pages. But, my client is upset as he (and he thinks many of his clients) have the old website cached in their browsers and won't know how to clear their browser cache. Is there anything I can do to overcome this and if not, what sort of time will browsers finally stop using their cached pages so I can at least go back to my client and tell him that his clients will finally start to see the new website?