Old 60's Lava Lamp In Need Of Repair

[Malia]

Hey all!Quick question for ya'.

I have an old lava lamp,cannot screw off top and coil IS at the bottom.
Lava is in a big ball shaped like those old jelly-like bathroom scent things behind the toilets.

H2o is an inch and a half away from the top with some lava embedded on top glass.
It heats up nicely but lava will not flow.

Do i need to replace lava?And if so,how do I screw off lid??