How old is too old for shellac?

[KingwoodFan1989]

I have a can of Bullseye Sealcoat (de-waxed shellac) that's about 3 and 1/2 years old, and it has been opened for most of that time. I didn't want to waste it, so I tried it out on a project I'm working on. Initially it seemed fine, and it worked fine on some of the smaller project parts. However, on the main part, I noticed that on the spots where it was thicker (especially where the brush left a little bit extra) that it wasn't drying clear. It was turning a white color, sometimes with a bluish tint. I've read that this can happen because of moisture in the air, but I'm wondering what the shelf life is for canned shellac? I tried applying some denatured alcohol to the surface, but it took several tries to even begin to make significant progress. I noticed another weird phenomenon, too. There are all these little water droplets forming on the of the drying finish, kinda like condensation on the outside of a glass or can with a cold drink on the inside.

Here's the thing, this blushing (as I've read it's called) effect isn't uniform. It's mostly in spots where the finish is on thicker, although it's still spread throughout. The shellac can had the lid on all this time, but could moisture still have gotten into it? I highly doubt moisture in the air could cause it to be this bad, as it's rainy but not too humid in my area. Is the shellac just too old? Sorry if this sounds like a rookie question (which I'm sure it might be), but I'd like to know what the probable cause of this is. Thankfully I didn't put it on the entirety of the project, so I can just sand it down, put another light coat of paint on, and then repeat with new shellac if it's just the age that's the problem. 

Also, as far as shellac application goes, I'm doing this on a drum shell, and it's around 20" in diameter, so I end up with a lot of unevenness in my finish since it starts drying well before I can get around to the other side. I don't really want to use spray finish right now, so with brushing, should shellac normally dry clear even if it's uneven (i.e. if there are some light runs or thicker spots)?

[jteneyck]

SealCoat has a stated shelf life of 3 years, so you're beyond that, and maybe way beyond that depending upon how long the can sat in the store before you bought it.  Throw it out.  

You should be able to get rid of the blush by spraying or wiping those areas with denatured alcohol.  If that doesn't work,  try lacquer thinner.  If that doesn't work, then I would strip it all off with a chemical stripper.  It's fast, complete, and won't damage the underlying wood like sanding may and usually does.  After you have it stripped and neutralized, if you still want to use shellac get some fresh stuff and pad it on.  Look up padding shellac.  An alternative is to get a can or two of rattle can shellac.  Either approach will give you a uniform, thin coating. 

John

[MikeBob]

Ditto, you an test it, pore some on a piece of glass se how it runs and dries, but from you said I would not bother, for the $11.00 just get a knew can.

[bhh]

Ditto, you an test it, pore some on a piece of glass se how it runs and dries, but from you said I would not bother, for the $11.00 just get a knew can.

This follows my risk:reward equation (I use for old glues and finishes).   What's the cost (effort) if it fails and you have to undo and redo vs. cost of a new can.

[MikeBob]

Shellac and high humidity do not interact well. Even fresh shellac put on as a finish in high humidity can/will blush.