These LDPE bottles are perfect for storing thinners, custom paint mixes, etc. The bottle are of high quality and the caps seem air-tight. The quality is comparable to that of Vallejo dropper bottles. I put lacquer thinner in a bottle and 91% IPA in another 10 days ago. I haven’t detected any loss of those solvents due to evaporation. The 50 bottles will serve me forever. If you need dropper bottles, check them out.
At this price you can’t go wrong even if they don’t work out.
However, I do “pine” for the days when bottles like these were glass. Nowadays even if you could find them they would be more expensive to buy, not to mention ship. Personally I’ve had more long term luck storing items in glass as opposed to plastic. On the other hand glass doesn’t respond well to squeezing!