i have the best results by using my lcd separator machine to warm up the glass/lcd and the Yaxun YX-D02 to separate the lcd/galss from the frame
The temperature I use is 85-95 degrees.
Keep the phone facing down on the hot plate for up to 2 minutes, to let the glue warm and melt uniformly. the use the tool to SLOWLY separate the lcd/glass from the frame.
Remember that on the upper part there's the flex connected. and on the lower part you need to help the small flex to come out from the back.
These are the tools I use.
Cheers
X4ce