Moving an Untame Giant Day Gecko

[grumboli]

Hi everyone,
I have an untamed giant day gecko (phelsuma grandis) that I've had for a couple years now. We are moving to a new country in a few months and are unable to take him with us. We have a great new home lined up for him though. The only issue is, he is untame and we are unsure how to move him.

The tank he is in has coir and plants in it; it probably weighs over 100 lbs. Especially with all the water we put in there to maintain the humidity. So carrying the entire enclosure down a narrow flight of stairs would be near impossible.

Does anyone have any advice on how to remove the gecko from the enclosure, causing the least amount of stress possible, so we can empty the tank and get it moved? He's super jumpy and has gotten out before when we've left the door open a few seconds too long when feeding.