Take them to a shop.
XTL software is easy(ish) to find, programming cable will cost you some money.
Not sure about APX software, we skipped those. Cable is not free, though.
If they were issued by an agency, take them to the agency, they should be more than happy to wipe them.
If they are yours/your employer, contact the radio shop that the local agency uses and ask them nicely. They should like to make sure used radios loaded with their information doesn't end up in the wrong hands, and may wipe the radios for free. I know I certainly would.
Or, try a shop. Probably easier/cheaper than procuring software and cables. Plus the learning curve is a stone cold b***h if you havne't done it before.
You can just 'erase' the radios. You have to take the old codeplug, create a new rx only conventional personality, load that in and remove everything else.
If the radios are on a trunking system, your only option is to take them to the system admin, since it'll take a system key to modify the trunking part.
And good on you for doing the right thing. This sort of thing is a big PITA for me. People take old radios at work and just toss them in the e-waste bin with all the encryption/programming in them, not giving a single thought about it.
