Rubber dropper tops bad to keep on?

[dc32]

I saw an intro video the other day and she mentions the dropper tops are porous and can be bad for the e-liquid if you leave them on...I am a newb and was all gung-ho about it and discared the normal tops before realizing I'd need them again

The bottles were from totally e-liquid and I couldnt' find any disclaimer saying to keep the regular tops on...So I just rapped the tops with some saran rap incase the rubber stoppers as tops are no good

any info on this?

Thank you

[Sun Vaporer]

I have had not issue with them--but others say they do--when in doubt, play it safe and place a normal cap on (childproof is advocated)---Sun