No you can not affect the cache the program reservers
If the data file is large, I would suggest you start a new file.
You can try the condense function in menu file?utilities>condense, but in my experience it rarely works accurately. If you do try that you need to first print out all the critical financial reports, do it again after the condense and compare, they must match
Or the first two utilities on this page do work to create a new file going forward
http://www.q2q.us/indexutilities.htm
I am not affiliated.