The sheet metal screws I use are the ones that are used for fastening metal sheets onto metal buildings. They have a metal cup that fits up against the head of the screw with a rubber washer on them. When the screw is tightened it presses the rubber washer against whatever it's being screwed into and forms a seal this way. Capt. Sully is the one who told me about storing DN this way and I believe he uses a plain sheet metal screw without the washer and has had no problems storing it this way. A small amount of the DN will seep out around the edges of the screw and will form a seal on it's own. The one thing you don't want to do is try and tighten the screw so much that it ends up tearing the hole out which will blow any chance of getting it to seal. To get the DN out you just back off the screw a little and the DN will start to flow out. You don't have to take the screw completely out for it to start flowing. Just draw out however much you need into a small container and reseal by tightening the screw. Doing it this way is only for those who brush their top coats. You would waste too much top coat drawing out enough to dip baits this way and you sure don't want to pour the contaminated product back into your storage container as it would ruin the whole batch.
Another method of storing DN for those that want to dip their baits is to store it in a Mason jar. (can't remember who told me about doing it this way method........sorry) You will need to use Bloxygen with this method every time you reseal the jar though. After dipping your baits just spray a little Bloxygen into the Mason jar, seal the lid and turn it upside down for storage. I'm presently storing it this way and it seems to be working as I've had the latest batch of DN stored this way for about two months. Saving your baits until you have quite a few to top coat is a good idea as this will minimize the number of times you expose the DN to the moisture in the air which is exactly what starts the curing process.
Let me say this about DN. Is it a pain in the butt to store? Yes, without a doubt. But once you get around the storage hassles it's the best top coat I've found (and I've tried several) for putting a durable, clear, UV resistant coating on your lures. This is just my opinion and I'm not trying to re-start the dreaded top coat wars found in previous posts. If there was only one "best" then there would only be one top coat as everyone would want to use it.
just my ,
RG