So how exactly do I do this?
1. If you're on PS3, then go to the Game Data Utility Folder and go to the "New Vegas DLC" file. Press Triangle and select Delete.
NOTE: if you have any of the Preorder DLC, download it before starting up the game, or you'll lose those items as well.
2. Start the game up. Load your file. A warning will pop saying that some items will be unavailable because files are missing. Ignore it and continue loading the file.
3. Once the file is loaded, you'll see that any items from Dead Money are gone. HOWEVER, you will still have any caps and normal items that you got from the DLC, levels earned, and skill points distributed (including those from skill books).
NOTE: If you had selected any perks that were part of the DLC when you leveled up, you will lose them, and be unable to get another perk in it's place, because you will still be at Level 35.
4. Save the game and Quit to the XMB menu.
5. Redownload the Dead Money DLC. This may take a while depending on your internet connection.
6. Start up the game and load up your save again. Proceed to the Abandoned Bunker and towards the Radio. You'll be knocked out and start the DLC all over again.
7. Finish the DLC however you like and make sure to turn those gold bars into caps.
8. Rinse and Repeat however many times you like.
NOTE: Doing this, you'll have access to infinite skillbooks, meaning infinite skill points. HOWEVER, there is no Wasteland Survival Guide, and the Duck and Cover! is glitched under Domino's bed, meaning that you won't be able to use this exploit to raise these two stats.