Question - How to clear up a foggy 90's lava lamp

[Spencer541]

I'm going through my whole collection and running into a few lava's that are very foggy such as this cranberry pictured below, a green one, a teal one etc.  These are all globes from the 1990's.  What can I do to help clear them up -

Should I run them?  

If so how long?

Frosted bulb or clear bulb?

Right now they are running a 4 hour cycle twice a day with about 12 hours in between cycles.  Is that enough or do they need more run time?

Thanks.

Pictured below is one #16 black and two #18 cranberry lamps sitting next to each other.  Obviously one is doing a little better then the other

The tape on the globe is just there to let me know where the liquid level was when I boxed them up years ago. 

[Mortebianca]

Wait, so which one should I do? :O
-4 days on, 2 days off
Or
-1 Week on, 1 Week off?

[Bohdan]

Run the lamp for 8 hours a day for 3 or 4 days then let it sit for a week. Then run it again for the same time. As a month goes by see if the lamp starts to look better.

[Mortebianca]

Well thanks for all the infos, I really appreciate them. I'll start your method right away, and let it sit for a week before cycling again. Hope being next to another lava lamp is not hot. I'll also post some pictures of the lamp in question and compare it to the Mathmos I have.

photo_2020-02-23_04-15-52.jpg

photo_2020-02-23_04-15-56.jpg

photo_2020-02-23_04-16-23.jpg

photo_2020-02-23_04-17-20.jpg

[Spencer541]

Well it took a month a about two weeks of running 8 hours a day for a couple of days on then a few off but as you can see in the picture this purple lava went from a foggy mess to crystal clear.  I am truly amazed it recovered.