pill bottle keychain thing.i have some of those cheap 5$ for 3 pair 30dbs from home depot a single pair can pack down into a cheapo pill fob and they are washable/reusable but on hot days they pull out a lot of nasty stuff out of my ear
Yup... these work great for that, and many other things. http://cgi.ebay.com/Geocache-Bison-Tubes-5-PACK-with-Inner-Vials-Geocaching_W0QQitemZ220477215846QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item3355775466#ht_500wt_856
Bought mine with a little key chain case/tube and they were some of the best noise reduction rated ones I found. I use a bit of electrical tape to be sure it doesn't come open. Should be easy to find plugs with a case like that at Dicks, Gander Mountain, etc.
A radio station once gave me a pair of ear plugs in one of these containers. it had a short bead chain through one corner, it was secure and easy to open but of course by the time I decided to start carrying earplugs I had lost it.
I carry spare foam earplugs at work using a safety pin. I imagine you could attach a safety pin to a split-ring somehow. Go buck-nutty with that idea.