Van- for cleaning tuners, I'm gonna guess you mean the tuning capacitors. As they are such critical devices, you should just as well leave them alone. It is possible to detune the reciever by spraying contact cleaner in there. I have 80 year old radios that still outperform most of the modern stuff, and I've never touched the tuning mechanism.
I love this Deoxit primer, but I would avoid the relay cleaning steps. At work, we have been trained to never, never, pop them open, and if there is that one time where you must, to only use specialty tools for messing with them-ie point benders, burnishing tools, etc. So if your amp/reciever is otherwise working, I'd just as well leave that part alone.