Nope. You can just pop the pistons out if you want but, take note of where they came from. Don't interchange their positions. Having said that - if you can't get replacement seals (and you might damage them taking the pistons out or putting them back in) then be very careful...it might be better to split the caliper after all.
Clean the seals with fresh brake fluid. Wipe the caliper out using lint-free cloth. You can wash the caliper but, make sure you dry it in a warm oven to remove all water vapour before re-assembling.
Does anyone actually know whether or not seals can be sourced?
Cheers guys I always try to search for an answer on the message board before posting such a question but "caliper cleaning" didn't return me the post below...