removing abstract field when sporting to a bibtex file

Hi, I am looking to find a way to remove abstract field while I am exporting my library to bibtex file. Actually, by syncing the library to bibtex file, abstract field is synced which is not favourable. In fact, bibtex buffer has limitation of 5000 characters and high number of characters in abstract field violates the buffer limitation. So I should delete all the abstract field after syncing to bibtex manually and it is really time consuming. I would be appreciated to suggest me a solution.