Having fun and games with an old Chinese Anchor Lamp - stuck NRV. Its a slotted head but hauling it out of the tube was a problem. So, out comes my go-to freeing solution 50/50 Acetone and automatic transmission fluid and half filled the tube. I replaced the pump and gave it a tap with a soft hammer - hey presto! the nrv burps away like a good 'un. Now to get it lit and ready for the Santa parade.......