I just purchased a discontinued (nonreturnable) keg off craigslist for $12 to turn into a brew kettle. Now, I've read the articles and watched all the videos on removing the spear, but for the life of me I can not get the spring to pop out. I've been able to fit a tiny screwdriver in the notch and I got it to budge a little, but before I can get it to pop out either the screwdriver will slip or it'll begin to strip the edge of the spring. Any suggestions?