From my wonderful colleagues I got the idea of doing a "blessing of the backpacks" as the children of the congregation go off to school.  It's not a new idea -- Christian churches have been doing it for years, and apparently some UUs, too -- but I had never heard of it before.  Churches often apparently put some sort of zipper pull tag on the backpacks.  Here's an example found on Pinterest:


A couple of colleagues shared their ideas, and some images, in a closed Facebook group, which started me thinking.  I'm fairly crafty with things like this, so I knew I could come up with something.  I was inspired by Karen G. Johnston's example created by her DRE and a member, but couldn't figure out their fancy knots:

http://awakeandwitness.net/2015/08/27/blessing-of-the-backpacks-a-mini-primer/

But, on the other hand, I do have some tricks up my own sleeve.
Here's my prototype:

My prototypes cost me over a dollar each to make, but to make in bulk they'll cost less than 30 cents apiece, not counting tools or jump rings.  You start with 1-inch bottle caps, the kind that are designed for jewelry and crafts.  You can get them in silver, black, mutli-colored, patterned -- really any way you want.  The ones that I used are also described as flattened bottle caps, but you can get ones that are more bottle-cap like.  My price of $0.30 each is based on using these:

Print out your pictures, sizing your pictures to one-inch.  Your church logo or the UUA logo would work nicely in these.   As you can see, I used one of my Zentangle chalices, on a star-shaped background. Please do check with me before using my artwork.  I liked the symbolism of the star for kids who are all stars. 
I can get about 45 onto one page.  And here's the big secret: I print these out on full sheets of label paper.  That makes my chalice self-adhesive, which simplifies what could be the messiest, gunkiest, error-prone stage of the process.  Label paper seems pricey, but when you price it out per item if you're making a ton of these, it's less than one cent per chalice.

You'll need to acquire a one-inch circular punch.  I like Martha Stewart's punches for my scrapbooking, so I got hers. 

Punch out your circles on the label paper.  And the next step is that BEFORE you remove the backing, stick a one-inch clear circular epoxy sticker on top of that circle.  This makes the backing much easier to get off, really.  And you're going to stick the epoxy sticker on anyway.  So do it in this order and trust me.  Then just remove the label backing and pop that circle into your bottle cap.  The bottle caps I got came pre-punched with holes and jump rings in them, so it was important to line up the top of the sticker with the top of the bottle cap.  Bottle caps are cheaper if you don't buy them punched, though, so you'll need a bottle cap punch, and then jump rings or split rings if the hole it makes is too small for your ball chain.  Probably any metal punch of the right size would do, but they sell ones specifically for this.

Jump rings are not priced into my 30 cents each, but they're less than a penny each, if you buy bulk.  This is where you have a difficult choice to make, because jump rings open up very easy if a kid is pulling on this backpack charm, but split rings are a pain to put on.  My more expensive bottle caps came with split rings already on them.  I think there's probably a tool to make those jump rings easier (I do see things called "Split ring pliers, but they just look like needle-nosed pliers with a sort of hook on the end).  If someone knows if these are helpful, please inform us in the comments.  I mostly just juggle around and pry with my needle-nose pliers until I get them opened.  They're like little mini key chains, and you know what a pain it can be to get keys on and off a regular key chain!

So that's the chalice bottle cap part of the charm done.  Next I got some bright peace sign beads to add on.  I'd add UU beads, except that I don't have any alphabet beads where the hole is big enough for the ball chain to go through.  But that would be a nice option.  Turns out you can get packs of all Us. 

And then lastly add a ball chain key chain of about four inches.  You can get these in packs pre-cut.

And there you have it!  Cute backpack charms for the blessing of the backpacks!