I recently noticed a sudden drop off in my commissions (to $0/day) and I am wondering if the problem may have been cause by my clearing of browser cookies. Is this logical? Thanks
No all user at a same time do not clear there cookies but there can be tracking problem at affiliate end.
Like Empyre mentioned, the problem would be on the tracking or customer's end, not yours. Since those issues are usually out of your hands, double check your site and make sure all links are working correctly. If you can't find a problem, try switching out links to a competing offer in a different affiliate network (if possible).
Tracking from your network would be the cause of this or some other problem with your network. Your cookies have nothing to do with this.
Clearing your own cookies wouldn't affect this, if users did this it might but as was stated they wouldn't all clear them at the same time. Contact your affiliate program and see if they can help determine what the issue might be.