Are they the velcro with just a probe glued to it?
If so, here's what I'd do with them.
Cut the velcro off. It's cumbersome and annoying and difficult to get good and tight. Get some sort of zip tie to hold them on. I'll tell you what I use if you'd like to know.
http://millepede.com/products/mille-ties/20686
Wrap them back up, put them in the bag and let them collect dust for a while. They aren't eating anything and you don't have to shovel anything out from under them.
The clamp sensors are great. I use mine almost daily, BUT, I still carry the probe type sensors because the clamps don't work well with small lines (under 3/8" or so) and large lines (over 1 5/8")..
If you know for 100% absolute certain that you will NEVER, EVER, EVER encounter those line sizes, then go ahead and dump 'em, but I'd hang on to them.
Then again, my wife calls me a packrat among other nasty and unrepeatable things...