No, the connectors cannot be re-used. If they are crimped connectors, they are one-time use and cannot be removed without destroying them. If they are the old-style assembled using wrenches, it is possible to take them off, but as Mr. Zelin says, so cheap they aren’t worth the labor unless you are on a desert island with no other options.
OTOH, some of us are frugal enough that we use those kinds of surplus items to make adapter cables with. We put connectors of some other type on the other end of the cable to make jumper/adapter cables for various miscellaneous uses.
If you have a significant number of them (dozens?) and they are in relatively good shape, it might be worth offering them on Craig’s List or something. (“recycling”) If you are in PDX, I’ll take them off your hands. 🙂