By David Leonhardt

CONSUMER ALERT: do not mix your food container lids. A yogurt container lid is NOT the same as a margarine container lid, even if they look the same. How do I know this? Well, here is my story.

NOTE: This is all more or less true, and very frustrating. Why should I have to throw out a perfectly recyclable piece of plastic, just because somebody embosses a "5" on it?

We live in a very hoity-toity county. Sure, it might look like just farm country. A lot of the houses might seem a little worse for wear. But we are very picky about what plastic we recycle. We recycle only those numbered 1 and 2. 3s and 4s and 5s and other numbers are just not good enough

In case you did not know, your plastics are numbered. On the bottom of most plastic food containers, there is a number, usually from 1 to 5. I suppose 1 is the best, since anything with a number of 3 or more just is not high-class enough for us to recycle in this county.

Sooner or later, it was bound to happen. My overactive curiosity got the better of me and I emptied the fridge to try to figure out this plastic numbering thing. What else does one do in the middle of the night when his newborn doesn't want to sleep?

My wife came down to the kitchen. "What on earth are you doing?" she asked in an attempt to inject some sanity into our all-night vigil.

"Just snacking," I replied.

She scanned the table, covered with yogurt, hand cream, cream cheese, plum sauce, juice, shampoo, and an empty ice cream bucket (and many more containers – too many to list on a single web page). "OK, I'm not actually eating any of these," I admitted. "I'm looking for numbers on the bottom to see which of these containers is high-class enough for us to recycle."

"You are NOT recycling our brand new tub of margarine," my wife declared. "And that juice jug is supposed to last us a few more years."

"Of course," I said in my most believable comforting tone. "It's just a curiosity thing”.

"Oh, one of those," my wife sighed.

"You see, both the yogurt and margarine containers are made of PP."

"PP?" my wife asked in horror.

"Yes, PP. Plastic number 5, also called Polypropylene."

"Oh. That's a relief."

"But the lids are not the same material. The yogurt top is a number 4, whereas the margarine top is a number 2."

"Plastic is plastic," my wife said.

"Not at all," I replied. "Each plastic is different, and some tops and bottoms don't even match. There must be a reason they use for the yogurt top a plastic of such poor upbringing that our recycling program rejects it. It might be dangerous to mix them up."

"That's silly."

"Then why else would they need three different plastics for two simple containers that are used for essentially the same purpose under the same conditions?"

My wife turned around to leave. "Wait," I cried. "There's more."

"That's what I was afraid of."

"The parfait container has no number. Does that mean it's undercover? The lid is a 4, which means we can switch it with the yogurt lid, but not with the margarine lid."

"The parfait container is clear. You can see through it. Maybe they can't recycle see-through plastics."

"Exactly what I thought," I exclaimed. "But look at your shampoo. It's in a clear bottle, a number 1. But the matching conditioner, which is not clear, is in a number 2."

"That makes sense," my wife assured me. "Maybe."

"Not really. Number 2 is used in the margarine lid, the big ice cream bucket and the vitamin jar. Besides, here is another margarine container made of clear plastic, and it is also a 5 with a 4 lid."

"This is way too confusing," my wife said. "We have a baby to attend to. She just can't seem to sleep."

"With all our containers mixed up like this, who knows what the world is coming to," I cried. "No wonder she can't sleep."