I have an old key fob that I want to erase and reprogram to open a lock on our shed. We've had a problem with the neighbor's kids rooting around so we got a lock for the door. The lock came with one key fob but I need two so both my roommate and I can have one. It's a simple key fob: no buttons, just place it in front of the lock for a moment and it unlocks. I have an old key fob that worked the same way that I don't use anymore so I want to erase the information from it and add the information for the current lock. I know how to put the information on there but not how to erase the existing information, which needs to be done before I can reprogram it. I know that if I demagnetize it that will erase the information but I'm worried that that would lead to it not working at all. I can't just buy blank key fobs right now and we can't share the one with our schedules, so what's a lifehack that can quickly, easily and cheaply erase my key fob so it's blank again and I can program it for the new lock?
You actually want to reprogram a key fob, not just erase (destroy) it. For that, you surely need a dedicated tool (hardware + software).
Before you do anything else, you need to know the technology involved (RFID, NFC, other...) and the details of that technology. It might even happen that your old key fob is not even compatible with the lock.
Sometimes, depending on the specifics of your area, you can find shops doing exactly the job that you want. They have the tools, the knowledge etc. Go there with both key fobs (the good one and the old one) and they will create the clone, if it is possible.