Would it help if you took them out of the bag to let them air out a bit?

I would say the same - just let them air out more. Leather sometimes really really smells. Tanning products can smell pretty funky. Maybe it just needs to dry out a bit?

What does it smell like? Is it just that you don't like the smell of full leather, or does it smell like something else?

If nothing else, letting it air out (fresh air, sunny day) would probably be your best bet.

Are these thin "Garment" leather or more like saddle leather (thicker)? Also what color? This may help me figure out how to help. (My first job was at a shoe repair shop, we also did leather repair and refinishing.)

All leather is not created equal, and the tanning process in cheaper leather does leave an odor. However, even the cheapest leather can be made to smell just fine and dandy if you're willing to put in the work. Here's my method:

First, get yourself a bar of glycerin soap. Pure glycerin soap. Not soap with glycerin in it. It's a big ugly orange bar, and you'll find it at the feed store. While you're there, pick up either 100% pure neatsfoot oil (NOT compound, compound is BAD) or Lexol Conditioner (the one in the brown bottle. Ignore Lexol's cleaner, which is the orange bottle, it's basically watered down glycerin soap.) If your leather is dark in color, you may use either. If the leather is light in color, you must use the Lexol. Neatsfoot will darken light colored leather.

If you have dark leather, or don't mind darkening your light leather, you can choose between the Neatsfoot and the Lexol based on other factors. The Neatsfoot should be cheaper. The Lexol smells better while in use. The Neatsfoot soaks in faster, and can be used to soften stiff leather faster.

Also fetch some appropriate sponges -- spring for the real sea sponges if you like, but the cheap little orange leather sponges are just as useful for your purposes, and easier to wash. Get at least two.

Now, using the glycerin soap, and a bucket of ice cold water, you want to lather the heck out of the leather. Do not submerge it in water. Lots of lather, very little water. Lather and rinse it repeatedly, without submerging it. If the leather gets waterlogged, the smell will get worse instead of better, and also the leather will stretch, which you do not want.

Now, wipe the leather off with a paper towel, and oil it with whichever you bought -- the Neatsfoot or the Lexol. Use a different sponge than you used during the cleaning phase. Oil it repeatedly until everything feels nice and supple in your hands, and then leave it out to dry.

So far, what you have done is a thorough job of basic leather care. In extreme cases, you might not have improved upon the smell. If you can still smell the tanning chemicals after a good cleaning and conditioning, you'll want to pack the leather in with some baking soda for a few days, and then repeat the entire process. If you're desperate and the smell is particularly bad, you can spray it with a cleaning product designed to remove pet odors from upholstery (don't ask why, trust me) and after letting that sit an hour, go through the whole thorough cleaning and conditioning process again.

Do not go straight to the odor-removing products, because it's quite possible that the otherwise good quality leather came about its odor honestly, through exposure to storage chemicals, packaging, or something else it met in the past. If that's the case, that first good cleaning and conditioning will do the trick.

If the smell persists regardless of anything else, you can kill even the foulest stink of the cheapest leather by doing all of the above and sealing it with mink oil when the leather is at its cleanest.

Oh, and always use cold water on any leather -- warm water opens the pores in the leather and leads to unwanted stretching, the deeper embedding of dirt, and other bad things.

Enjoy!

Have you tried sealing them in a large box with the drier sheets? I know I adore the smell of leather and would just be crushed if I got something new and it stunk. I'd try the drier sheets in a larger box.

Don't worry about the leather - leather won't suddenly start stinking your bag out for no good reason. Look at the gag. If that's a rubber bit, I'd bet that's your problem right there. At work, as far as I can, I ban people from smoking anywhere near my leathers, or from even standing near them if they have been smoking. Because the leather will absorb the smell.

Leather is very porous - go figure - and it picks up smells very easily. And rubber bit gags, some of them absolutely reek. In fact any that aren't silicone, and that's 99% of them.

I remember buying 500 rubber bits from Weaver Leather a long time ago, intending to make gags, but I had to send the whole lot back, because they reeked up my workspace. They were in a box, but you couldn't stay in the space with them, it was that bad. That was kind of when I really got the whole silicone thing. The smell is noxious chemicals outgassing. Next to leather in a bag, the gas will make its way in, and yeah, you'll likely get a reeky mess.

Not sure what you can do about it. You need an industrial smell extractor. I've seen products in hardware stores that are supposed to be able to clear up cigarette smells and non-specific odour infestations. They may work. And of course, you can try some of the suggestions on this thread. Toy Geeks advice sounds pretty sensible, though in general, I would advise people against washing their leather. It doesn't really do it much good, and can leach out the good oils you want in there to keep it supple. But hey, this sounds like an emergency. Hopefully you'll be able to get it sorted - good luck.