how do I clear a page, or set an item in a page to 'free'?

I've got a mucked up page in my db, and I can't complete a database dump
until a particular page is fixed/removed from the table. :(

Could someone let me know the proper way to go about making a change
such as this?:

1) Clear the page
or
2) Set the bad items in the page to 'free'

I can see the page with pg_filedump. (I know the page number)
Either method would suffice, I just need to get the job done :/

Thanks for any help you can offer,
Eric