We have some legacy 302 redirects in place on our site that should have always been 301s. We've now changed the redirects to 301s but various SEO tools (and presumably Google) still see the 302 redirect rather than the 301.
My question is, how long do 302s normally get cached for (if there is a 'normally' in this situation)? And is there anything we can do to speed up the process of recognising the change to 301s?