Long story short I had a microphonic bridge pickup in my '85 G&L El-Toro bass. It would squeal at moderate volumes and would pickup all noise when I tapped on it... fingers, a pick, whatever; way worse with the treble boost. Bad news. Anyhoo, I found the best solution would be to wax pot the pickup. I decided to do both the offending bridge and neck pickup. This is how I went about it with great results! I purchased parafin wax from the baking section, 1 pound did the trick. I also bought a pound of beeswax which was kinda spendy and not absolutely necessary but will lend to the durability of the wax when setup. I went with 1/4 pound of beeswax in 1 pound of paraffin. I melted the wax in an old double boiler to achieve a temp. of about 150 degrees F. After removing the pickups I found that the magnet on the bottom of the bridge pickup could move a bit when manipulated which was the likely culprit of the microphonics. I removed the wires from the circuit board and labeled them so I wouldn't mix them up Once the wax was melted and at right around 150 degrees I submerged the pickups and let them sit for 15 minutes to let the wax really get in there. I removed them, put them on a paper towel on a plastic cutting board and wiped the surfaces down so I only had wax where I wanted it. I let it set up and cooked my dinner! I proceeded to eat the Hell out of said dinner. As I did this I applied lemon oil to the fretboard and let this sit for a bit. I then re-installed the pickups . I used a bit of beeswax on each of the screws for a bit more purchase. I re-installed the neck, new strings and a slight micro tilt adjustment. I'm not sure what gauge was on the bass before so I'll let the bass sit for a day at tension before I decide if I want to adjust the truss rod. Plug and play. No more squeal! No more noise when I tap on the pickup. When the wax set up there was more wiggle on the bridge pickup magnet. Success! what a mean sounding bass.