We took down our shutters to paint a new color. They were held on the house by vinyl shutter locks. We cut off the tops and removed the shutters. We are now ready to start putting them back up. The problem is we can't easily drill out the old locks. I have read online to use a 1/2" drill bit. Are there any tips to getting those old locks out? We are at a loss as to why this is so hard.

Thanks for any input.