The last 3 or 4 times I have made an angel food cake, once it is baked and I turn it upside down to cool, the cake drops out of the pan!! Not from the inner core, but from around the outside edges of the pan.  This is the same pan that I have used for at least 20 years!!!   I do not ever oil it or anything...does anyone out there have an answer to this problem?  By the way, this is a Betty Crocker mix that only water is added to...the same kind I have used for years without problems. TIA!  

My Dad's Aunt...famous for her angel food cakes...always wiped out her mixing bowl and baking pan with vinegar.  She swore that the vinegar removed any traces of grease.  I never noticed it leaving a taste on the cake.  I don't know if that will eliminate your problem, but it couldn't hurt to try. 

Thank you for that suggestion!!!  You can be sure that I will be trying that the next time I bake an angle food cake.