What do you do when you're cleaning out the fridge, and you have to dispose of items that are semi-liquid/semi-solid (like soups and stews and spoiled milk)? You can't put them in the trash, or it might leak, and you can't put them down the drain, or it might get blocked up (unless you have a garbage disposal, in which case, ignore this tip).
Put a strainer/colander in the sink, and dump all the soups, etc. into the strainer. The liquids will drip through and go down the drain, and the solids will stay behind, to be thrown in the trash. If you want to be really thorough, run some hot water over the solid gunk to dislodge any sticky liquid or jellified broth before dumping it all in the trash.