When you buy bottles of Coke or Pepsi in Japan, it's not uncommon to find plastic packets attached to the top with little bits of various types of junk in them. Often these items are trinkets to dangle off your cell phone or "collectible" items following a certain theme such as small plastic figures of Snoopy or the characters from the animated series Lupin III. Quite some time ago, I was even compelled to collect a series of small (very cute) Christmas ornaments of the Coca-Cola polar bears (I still have them in the closet in a Christmas tin). Most of these items are decorative and completely impractical though you'll occasionally get something of extremely limited use such as a magnet or a clip.
Since Coke Zero was only introduced to Japan relatively recently, 1.5 liter bottles of that beverage sometimes have these little bar magnets hung around their necks. If you click and look at a bigger version, you can see the left end of the magnet is a little Coke bottle shaped "window" to the back of the bar.
Today, I bought a 1.5 liter bottle of Diet Pepsi with a Bugs Bunny packet attached to the top. I didn't pay much attention to what it was since I was mainly picking it up because it was cheap. From the appearance, I thought it might be a little calendar or stickers. When I opened it up, I saw it was full of little papers. Before reading the Japanese, I thought they might be for cleaning your eyeglasses though that did seem like a rather peculiar thing to attach to a bottle of soda.
When I looked more closely, the package said "aburatorigami" on it. The rough translation of this is "oil taking paper". I remembered then that I'd seen these types of papers before in the hands of the office ladies at my former job. They rubbed them on their faces on occasion to remove oil from their skin. Supposedly, these are effective in removing sebum in such a way that make-up applied after a mop up with these papers is less likely to crack or deteriorate throughout the day. However, since I often saw women using them in midday, they may be commonly used for all-purpose oil removal.
Given that this is an item used to conduct what could be considered personal hygiene maintenance, it seemed an even stranger thing to be attaching to the neck of soda bottle than eyeglass cleaning papers. While doing a little research on this type of item, I did discover that they are distributed with company messages, logos, or advertising much like matchbooks in the U.S. or pocket tissue packets on the streets of Tokyo. There's a web site which seems to specialize in producing these papers for companies to give away to prospective customers. It seems that they are appropriate for all types of businesses from dentists to lacquerware makers to beauty salons.
The bottom line for a company that chooses to distribute these papers does not appear to be how appropriate they seem to be with the type of product they're given away with (like soda pop) but appears to be their desirability and usefulness to nearly anyone who gets them. Much like pocket tissue packets, they seem to be the sort of thing most people wouldn't mind having handy. Well, everyone except me. Mine are headed for the trash bin.