Are Plastic Bottle Caps Recyclable?

A friend sent me this e-mail, but it sounds like an urban legend to me:

Please remove the plastic caps from all bottles before recycling them. The caps themselves are not recyclable and if they aren’t removed, the recycling company discards of the whole bottle. They don’t bother separating them.

What’s the straight dope?

Plastic bottle caps are recyclable. However, there are usually made of a different type of plastic from the bottle (often polypropylene for the cap, and PET for the bottle). Therefore, yes you should always separate them, as it makes things a whole lot easier for the recycling people. I figure, you’ve just had to take the cap off to rinse the bottle out, right, so why not toss them in the bin separately?

Whether or not the mixed plastic would cause the firm to bin the bottle or not, I can’t say. Bear in mind that plastic waste is not necessarily melted down (in which case it would have to be all one type). Often it is shredded and used to make building insulation, etc.

This page mentions the different-plastic problem, but also adds a reason I hadn’t thought of - a sealed bottle is harder to crush.

I read in some scientific magazine (may have been Chemistry and Engineering News - the one that the ACS practically gives away to its members) that they chip the whole mess up, and one of the types of plastic floats and the other doesn’t in water, so they can skim off the layers.

Anyone else heard this?

Yes. It’s called “flake sorting” - the plastic is chipped or flaked and what was bottles (#1 or PET/PETE) will float on water and what was caps and neck rings will sink. Caps are usually #2 HDPE, but can also be #5 or #6 - facilities that accept anything other than regular household #1 and #2 are rare.

As a result, the caps’ fate is very often a one-way trip to the landfill.

Earlier in the processing stream, they want the caps off because A: it’s less “waste” for them to deal with, and B: capped bottles have a way of exploding when compressed into bales for transport to the processing facility.

What’s a #1? What’s a #5? Here’s a chart of the numeric recycling codes for plastics.

Our local recycling scheme accepts codes 1, 2 and 3. So no bottle caps in my blue bin.

Well if you cap it loosly, crush the bottle, and then tighten the cap, it stays crushed and takes up about 1/10 the bin volume. Pity the recyclers don’t like it though.

Our trash collection company says to put both the bottle and the cap in the plastic collection sack, but separately. This makes both crushing and sorting easier.

Of course, just to confuse matters, nearly all soda, water, or beer bottles here are deposit bottles. If they have a screw-on cap, we are asked to return it with the cap on, so that the drops that are left inside won’t spill and make a mess and/or attract bugs. When the bottles are sent back to the bottling plants, they are run through machines that remove the caps and separate them for recycling before cleaning the bottles for refilling.

There have been a couple of big charity campaigns around here where people were asked to collect the polypropylene lids of plastic milk bottles - supposedly because some plastics company or other would swap them for a sizeable donation. I started a thread about it here:

(I notice I never returned to complete that thread - for the record, I was unable to trace the story back to any reputable source - it was FOAFs all the way). I still see charity collection schemes for these plastic tops cropping up now and again though - dedicated collection points next to the service desks in shopping centres, etc - but nobody ever seems to know the pertinent details.

That’s odd - the lids of my plastic milk bottles (Tesco, 2- and 4-pint chiefly) are LDPE (code 2). Those are acceptable in our local kerbside recycling scheme, which takes 1, 2 and 3.

Most soft-drink and squash bottle caps are PP, though.

Great, now I’m gonna have that song stuck in my head all night.