Apple doesn't provide the ability to nuke the old email addresses AFAIK, but you can contact the support folks and check on that.
If you only send from one address via the sequence described, then the random addresses won't pile up, and you'll still received the "misaddressed" messages until the addresses sort out.
The alias stuff you're probably referencing to earlier is available via the iCloud web site. Log into the iCloud.com web site, click your name in the upper right, select help, and navigate to the mail aliases help.
Back on the main iCloud web page, launch mail (in iCloud web site), and follow the path via the preferences stuff.
The .mac, .me and .icloud addresses also tend to get associated with Apple IDs, too. Delete with care.