...unless you have a BGA rework station just sitting around doing nothing in your garage, sell it on ebay for parts and just buy another one. Someone with a BGA machine would probably buy it off you. Once you have that machine and know what temps to set it at and how long, it is actually an easy process. The only problem is those machines are around $5,000 to $25,000. And, no, you can't use a $20 heat gun. Trust me. Just ask my old Xbox 360 motherboard that I tried that on several years ago.