Open Bottle

[TemperMental]

I have 2 Century lamps and wanted to open them, for no reason really.  I opened while the lamps were off/cold and heated them with small plates on top.  I noticed some changed right away... took much longer for them to heat up, some strange wave action rippled through the liquid, the clear liquid lamp immediately became slightly cloudy.

I closed them while the lamps were on/hot, and then turned them off.

Can anyone tell me what might have happened to them and if this will cause problems?

Thanks

[TemperMental]

The clear one is already starting to clear up again. Thanks for the input. I thought I read on one of the discussions that you should never recap or close the bottle either hot or cold, I can't remember which one?