How to delete all security groups on Amazon ec2?

I've created new EC2 spot requests over the last weeks. A new security group was created for every request. When the spot requests were deleted the security groups were not deleted. I've hit the 100 groups limit and want to delete them. The EC2 interface apparently allows only one deletion at a time, which means I would have to make 300 clicks to delete these groups. Or is there a better way to delete multiple security groups with few clicks or lines of code?