Removing old, closed accounts will have virtually no impact on your credit score but that is most likely a moot point since there is little or no chance that the credit agencies will remove them in the first place (assuming the old account information is accurate).

Closed accounts remain on your credit report for at least 7 years, good or bad.  Good accounts probably help your score and are unlikely to hurt your score when they age off.  Closed accounts with bad marks (late payments, etc) will improve your score as they age off, but you won’t be able to remove them yourself until 7 years since the last activity.  Don’t believe credit “repair” companies that promise to remove bad marks.