My Project Files keep getting bigger. How can I copy them to a new file and reduce the size?

hi,

My Project 2010 files with the Pro-Chain Add on keep getting bigger and reach more than 20MB.

I think that there is a way to copy them to a new file.

Can you please advise on a way to resolve this issue and avoid increasing the size of the files in the future?

thank you 

Vered