Leaving dropper cap on lure/oil bottle?

Is it ok to leave the dropper cap on lure making bottles of oil or lure; or should the bottles be stored with the regular cap on the bottle? Does it even matter?
Thanks in advance.
Rickey

I'd go with the cap as the rubber dropper might deteriorate and cause a leak.

Skunk essence will dissolve the rubber seal on dropper caps.

X2 and many other lure making ingredients will also dissolve the rubber just from the fumes, don't have to actually come in contact with the rubber