Whatever you do, DON'T spray a bunch of clear coat under there.
Cream hand cleaner is awesome for reconditioning wires. That's about all I got...
I clearcoated a hand polished intake several years ago and it yellowed.
It was a bugger to get the clear coat off,LOL
I've never tried hand cleaner on wires,but every year I take my plug wires off and wipe them down with Mothers Protector.
That seems to work pretty good.
I usually keep on top of my engine compartment,but every once in a while I spray the frame with Gunk engine degreaser and spray it off with a garden hose.Then I will take the paint that I use for my frame and floor and I will paint as much of the front frame as I can reach.
Before going to a car show,while everything is nice and clean I spray the inner fenders,firewall,etc.,with Stoner Trim Shine.
An air compressor is handy for blowing dirt and dust off of the engine.
I also take the valve covers off and clean them and put a couple coats of wax on them.
The air cleaner top gets polished,and heater hoses get wiped down with the Mothers or something similar.
Guy
Guy