Nokia :: E90 / Phone Memory And Maps

How do i free up the internal phone memory of e90..??? it seems to pile up everyday even though i clear the cache, delete all emails from nokia email, what else should be done to free this up.also Nokia maps slows down tremendously causing the phone to eventually hang or slow down. sometimes it works perfectly fine but usually it gives me the slowing down or hanging problem.could the memory problem and maps problem be related to each other?