
The best solution I’ve found is to throw the original caps away and seal the bottles with rubber stoppers of the kind used in chemical labs. I found an assortment from Amazon that sealed all the various sized bottles in my studio (with stoppers to spare). It has been over a month since I’ve been using the stoppers and none of my bottles have gone bad. I’m positive that one of my Galkyd bottles that is 3/4 empty would have been dry in the bottle by now without the stopper.
The only thing worse than buying expensive mediums is throwing out mediums that have dried in the bottles. I hope this will work for you as well as it did for me.
Please note that I have since developed a superior method of preservation using vacuum sealing. Read here. Rubber stoppers still work with larger bottles that are too big for the vacuum seal.
Brad Teare
Please note that I have since developed a superior method of preservation using vacuum sealing. Read here. Rubber stoppers still work with larger bottles that are too big for the vacuum seal.
Brad Teare
Brad Teare October 2013