Mini Maglight 2AA Disassembly

My 2aa mini Maglight that has been sitting in my toolbox and doing sterling service for over 10 years needs an upgrade and some tlc. I have a replacement led and a glass lens to replace the heavily fogged plastic one (scratches & brake fluid). Question: How do I split the head to get the lens in? It appears to have been welded together, heat & vice just produces deep score marks on the head. Any ideas, and before and smart*ss says buy a new torch, I have the bits already.

Thanks.

I had an old aa maglite stuck together. I soaked it in a small bag of gun lube oil for a few days, pulled it out of the oil, wiped it off, and twisted it apart with rubber gloves.

Not sure if the reflector will survive it, mine was already shattered.