Really old ones? Probably not many, they're so long out of service they're tumbling and their electrical systems are barely functional, if at all. If they ran their mission, then they're out of propellant anyway. There are a few old-timers that chatter when they get sunlight, but they're kind of worthless other than as a marker. Skynet 1A failed at ~18 months, so it probably had plenty of propellent left. Supposedly, the twat tubes quit, but if something happened to reconnect itself because of temperature variations and it started talking, someone could have found it. It may have been moved by those who knew about it and they were trying to deorbit a dead bird and that failed, or someone maliciously moved it because they could or were trying to do something else with it.