For e46 2001's they have the diamond shaped key which is recharged when in ignition. 99 and 00 keys you can replace the battery. More then likely indycar your going to need a new key. Theres a slim possibility it has just lost its programming and needs to be reprogramed to the car which dealer ships should do for free.
e30 keys you push down the rondel and side out to the right.