How can I delete all addresses from my Qt wallet without having to download the blockchain all over again from the scratch? I would like to find a bulk way to do it as there are a few thousand addresses I need to get rid of. These addresses are empty and they only cause significant delays to my interactions with the wallet.

I found a similar question indicating Pywallet (https://bitcointalk.org/index.php?topic=34028.0) as a solution but I have to manually remove each address one by one with it, which is not efficient in my case.