Just double wrap them in plastic....
Then dispose in garbage... Preferably in the hard waste...
(In Aus we have a pick up twice a year)
If your really worried, wrap RED duct tape in a big cross around the package... Universally the sign for "not so good, open with care"...
I'm not sure about world wide but as a general.... Even some items such as batteries, smoke alarms (radioactive units in them) can be disposed of in the garbage but only in small amounts... This is Aus only for sure...
How I know this- Customers constantly leave batts, fluoro's, smoke alarms etc with me (Like I want them or something.

) when they buy new ones.
I was worried about throwing so many at a time in the rubbish...
Apparently in "small" amounts your allowed to throw it in normal waste...
(I didn't really like that response though... Oh well I guess it's safe where it goes...??)
I'm fairly sure all waste, gets scanned for nasty bio etc material's.