If you have authentic Yamaha replacement potentiometers or electrically equivalent parts that are new (working) - then what you do with the potentiometer (assuming it's the source of the crackling) seems irrelevant. In other words if the experimentation you do with cleaners is limited to only the part you're replacing - then it doesn't matter much if you make that part worse considering you're prepared to replace it entirely.

And further assuming those are authentic parts - then the connectivity would be revealed by the pedal itself. No need for diagrams or instructions. Take a picture as the potentiometer sits connected before removal if you must.

A picture for the mechanical orientation would be worthwhile as well.

You have to be careful with "Electronics Cleaner" .... each brand possibly has a different recipe.

I would suggest... generally.... just get yourself a bottle of Isopropyl Alcohol... it is not a "cleaning agent" as such (which are generally some form of light solvent or de-greaser) , and in most cases is safe to use on electronics as a flushing liquid because it evapourates quickly, and leaves no residue.

Depending on the design of the Pot (Potentiometer), which is an electro-mechanical device, some use waxy lubricant for smooth movement, others use selected "non-stick" hard-wearing materials such as delrin, teflon etc for smooth movement.

For the lubricated Pots, electronic "cleaners" can sometimes also clean away the lubricant. While this shouldn't cause electrical issues, it can leave the pot a bit "jumpy" or feeling "gritty". In some cases, too loose, if the lubricant was also providing inertia for smooth movement.

Since you have no idea which is which (Pots) I tend to stick to using Isopropyl. You just spray/pour liberal amounts into the Pot then keep working the Pot back and forth so that any grit/grime/dust is flushed out. Grit, Grime and Dust (oh... and spilled Coca Cola) are usually the culprit in malfunctioning Pots. Isopropyl dissolves sugar (Beer, Cola, Coffee etc).

The other common malfunction is simple mechanical wear-and-tear or metal fatigue. The Pot works by sliding two electrically conductive/resistive surfaces across each other, shortening or lengthening the "resistive surface" thus changing the Resistance. If your FC7 has a lot of regular use, you could be wearing out "spots" on the moving surfaces. This isn't Yamaha's fault, it is just an inherent design weakness in all Pots. That said, some Pots are made better than others (they last longer), but they are also generally more expensive.

I have a 25 year old Strat guitar, I've had to change the Volume Pot 5 times, and the lower Tone Pot 3 times. I use them A LOT, but only ever in a certain Range (7-10)... so I "over-use" specific spots. They are CTS Pots, almost industry "Gold Standard". At first I thought they must be rubbish until I realised the cause.

That said, I now know how to replace them myself. I advise reading up on basic "Soldering Skills"... practice on scrap metal and wires. Tip: Do Not Overheat the Pot with your Soldering Iron... easily done, not repairable.

Soldering will help you in the other common cause of crackles and pops.... "Dry" Solder joints. Solder is prone to climatic conditions, and like any metal, it corrodes. Joints that don't look "shiny" may have dried out forming a poor connection or "High Resistance Joint"... sometimes just a dab with your soldering iron to re-melt and reset it will fix it.

Solder and Wires are also prone to metal fatigue. One would hope that as you move the FC7 Pedal that wires, joints, or the whole Pot is NOT moving with it. Check that wires are free and clear of moving parts. Equally check they are not being trapped or pinched by the casing when you re-assemble the pedal.

Thanks for those tips and cautions. I'm pretty sure climate is the culprit. I decided to try replacing the pots (rather then keep buying new ones) when a brand new pedal that had been kept in storage for several months started crackling and sending bad events straight out of the box. The next new one seems to be working fine, but I'd rather get to work on the other two pedals.

It's been a loooooong time since I've handled a soldering iron, so if the electronic part cleaner helps I'll put the pot aside for later.