When you create an avatar on Yahoo! Avatars, this avatar is automatically displayed in your Yahoo! Podcasts subscriptions page.
When you're logged into Yahoo! Podcasts, just click "My Subscriptions" to see your avatar and a list of your podcast subscriptions. Deleting your avatar should clear it from your Yahoo! Podcasts page.
Note: At this time, avatars can't be disabled for a specific alias. Your avatar is displayed for your Yahoo! ID and all profiles associated with that ID everywhere avatars can be used on Yahoo!.