How do I dispose of expired salad dressing, mustard, etc?

There is absolutely no reason why they can't be poured down the drain, other than they might be a little thick. They aren't Hazmat chemicals, for Pete's sake. I would pour them in the toilet; it's capable of handling chunky stuff...

Rinse the empty bottles and put them in the recycling.

why can't you dump them down the drain?

Poop goes down the toilet drain!

Why would mayo and mustard be more dangerous??

Don't you have a disposal that grinds up vegetable matter and runs THAT down the drain?

Of course you can rinse those things down the drain. Anything with chunks, like salsa should probably go down the toilet but that is also perfectly safe. After all, if you ATE the salsa, thats where it would go eventually.

Run very hot water dumb them mixing the hot water with the content and let it go in the drain

You are so smart to ask and not pour them down the drain. Call your city department that collect the garbage and trash. Our city has a special day when they collect these things and they dispose of them properly so the sewer and water is not contaminated with oils and fats. You get a STAR! :)

throw it in the garbage can and make sure it goes out to the street the next morning so it doesnt smell up your kitchen(even though its bottled).

Don't u want to recycle them?

Just put them in the garbage....