I got some really helpful feedback on my question about what to use to make a soft ball (or other toy) jingle.
Marion and Charlette suggested a whiffle ball, or a plastic golf ball. From what I gather, they are made out of pretty hard, durable plastic, and have holes in them.
Quite unfortunately for me, I haven’t been able to find any locally. (But I was happy to see I can purchase them at Amazon.com, so this is definitely an alternative for me in future!)
Part of the key here is to use more than one jingle bell! Duh. What a concept. So that was the main reason why my initial attempts were not working. Carolyn also suggested using a plastic film canister, and I found this also works pretty well… as long as there is more than one bell in there. In these days of digital photography, however, there just aren’t that many canisters lying around. And the few I have left I would like to keep using to safely dispose used needles in.
So my temporary solution until I can purchase some whiffle balls is still the ping-pong ball. This time, in addition to cutting it wide enough to slip two bells inside, I also punched some holes in it. Don’t ask me why, but it really does sound louder that way!
Thank you, gals, for your help! Now, does anyone have an answer for Charlette about where to find those really soft sounding rattles that go inside toys that almost sound like a harmony ball?