Am getting very frustrated with lids of paint jars becomming almost impossible to open if paint drys inside!
Any tips on keeping the lids free and easy opening and closing??
Thanks in advance for info!
If its a metal lid like Model Master, you can take a lighter and go around the the lid with the flame which will loosen it up. I had to do that the other day.
If the lid is plastic you can try holding it under hot water to loosen up the lid that way. I know MM does sell a ‘dried paint remover’ but you really don’t need it if you can get those 2 to work.
The hot water trick is good for any kind of lid.
Less chance of burning self or model ( 
as I learned a long time ago 
)
Also, cleaning out the lid / threads with a paper towel and wiping off the jar top will help----IF you remember to do it…I don’t, ever, but then I’m special-I guess.
Sometimes a delicate “touch of the wench” -actually, a pair of slip joint pliers (slipped to the large size) may be enough to persuade the lid; IF however, you find that you are gripping so strongly that your face is turning a deep crimson and your eyes are bulging, it’s OK to stop and try the hot water treatment.
So while you may feel your problem is unique to your bench; Don’t, we all have that problem----At least I do —
Good Luck and don’t let the paint dry in your brush or the glue get on your fingers…too often 
I keep an adjustable wrench at the bench for such things and I wipe the threads clean every time I open a paint jar… just don’t squeeze so hard that you shatter the glass!
I’m convinced that MM paint jars are designed from the get-go to gunk up like that.
I feel your frustration. The Mr. Hobby Aqueous stuff is what really drives me nuts. Five minutes in hot water and a locking wrench is what it took me to open a jar today, and it still wasn’t easy!
for Model Master, use a different lid, then you don’t have the problem to begin with
I put my LifeColor plastic lids on my Model Master paint jars, and use a phenolic lid on the LifeColor and Model Master/Floquil/PolyScale jars
search for vendors using " 28-400 glass bottles " and you should get hits for the bottles, and then the accessories for each bottle size give you the lid choices, containerandpackaging.com is one source if you don’t mind working with a minimum quantity
otherwise, you could just swap LifeColor and Model Master lids after they were cleaned, but, I have not used the MM lids on the LC bottles
Rex
One neat thing about the little square bottles of Testors enamels is that you can always get the caps off!
I mounted a little piece of aluminum to the edge of my workbench with a little slot cut out- the width of the slot equal to the width of those bottles. You can always grab a cap with a pair of pliers, but with a round bottle you cannot hold the bottle with another pair of pliers- it will turn if you apply much torque. They shouldn’t make round bottles! Square, hex, oval- whatever- just not round.
Try this several years ago my two daughters got me a set of strap werenches for fathers day, these things are a god send to remove stuck paint bottle caps try this. ACESES5
One way to get them off is to tip the jar upside down and then dab thinner down the rim, leave it for several minutes/hours then they should come off.
Obviously the easiest way to prevent is to always rub down the thread with some paper soaked in thinner before putting the lid back on.
i hold it by the glass and smack the lid hard a couple of times on a piece of wood, the sharp tap makes it give just enough to open it. havent had one break (yet!!) [clwn]this may not be a good idea but i am an impatient bugger [:$]
Use a thin swipe of vasaline on the threads when you are finished with a color. It works well.
I apply a tiny bit of beeswax on the threads of my Tamiya acrylics. It keeps the caps air-tight and prevent from sticking.
Some good ideas folks! It’s hot water and pliers here. Wiping the threads is a sure fire way to avoid getting a badly stuck cap. Square paint bottles? Do they still sell those? I didn’t want to date myself by admitting they were still part of my inventory Don! Not sure about Vaseline though, what would be the effects of it getting mixed with the paint? Model on!
I got this tip from FSM. Before closing a bottle, cut a piece of the shrink wrap the sprues come in a bit larger than the bottle opening. Place the plastic over the opening and close the lid. Bottles open easily unless you don’t use the paint for many many days, you than use the hot water method if it does
One small problem that can crop up with that old FSM tip.
If you put either plastic or aluminum foil over the paint jar, and then tighten the lid as tight as you should to form a seal,you have just created a “broach” for your plastic film.
You can end up with little discs that fall into the paint when you open the bottle.
If you don’t seal it enough to cut the plastic,you let in air.
(I had to fish out the plastic and alumimum discs with tweezers from all the enamel MM paints I sent to a friend when I switched to Acrylics)
Rex
I use a lot of the Model Master stuff in the round bottles. Things like strap wrenches and other kinds of wrenches do not work well to hold the bottle, as the label goes almost all the way around, and the wrenches just tear off the label and the bottle spins in the remnants of the label 
Don, I ran into that also.
Run a layer of clear tape around the bottle of paint when you get it. Both for grip and to help keep the labeling in case of thinner hitting the label.
Then, instead of straps or pliers,open the bottles with gloves with rough rubber grip palm/finger areas. Those work just exactly like those rubber discs intended to open jars in the kitchen.
Run either Vaseline or Chap Stick on your threads, and you don’t get stuck lids with that jar of paint again. Put that on the bottle’s threads, not the cap’s. If you have old bottles with paint dried on the threads already, put wine corks in the bottles so you can have the bottle sealed while it lays on its side, allowing you to scrub the threads clean before you lube them.
Switch to the cone type of Phenolic lids,(exhaling into the jar),and you never get a dried out paint again.
Rex
I’ve used a pair of slip-joint pliers to get those stuck MM lids off. It does play hell with the label but I don’t mind; it’s the paint inside that I need, not that label. One caveat though-I have broken one or two of those MM bottle using that method too. It seems there’s a rather abrupt point reached with the plier pressure, lol. Then, yes, time to buy more…[:D]
Yeah, I have broken more than that. They do break easily!
Vice Grips. There’s a fine line between tight and broken bottle though! Or, turn the bottle upside down and dribble a little thinner along the cap line. Let it soak a bit.