I’m confused. Did you IPA soak something from inside the extruder stepper motor, or are you saying you soaked the gear in IPA that is pressed up against the toothed gear by spring force?
Nothing from inside the motor. Just the gear assembly (the gray part in the image below). In my case, the gear/wheel inside the gray arm was not spinning freely. After soaking and cleaning, the gear spun freely again, and the extruder worked as expected. Hope that helps!
Ah I see. My A1 has a similar part. It’s not spinning freely, but it’s not rough either. It rolls but it doesn’t glide if that makes any sense. It’s not like it’s on a ball bearing smooth. It likewise seems to be pinned in place like yours is.
What ended up stopping my clicking/skipping was turning off tangle detection and dynamic flow calibration. I only have issues while printing and while using a 0.2mm nozzle. Something about my sensors isn’t right.
Anyway, would hurt for me to clean and re-lube my idler gear. I like doing maintenance anyway. 
I’m having a similar issue with my A1-Mini, and after only having it for 3 months. At first I thought it was just a worn nozzle, so I replaced the hot end with a hardened steel. And I made sure to change the settings menu on my machine. It then seemed to work for few days, but then the clicking and skipping started again. I checked for clogs and little bits of filament to no avail. After some more troubleshoot googling I took apart the extruder and the extruder gear did have bits of filament all gummed up. I cleaned it off and put everything back together, but it still wouldn’t extrude so I ordered a new extruder gear assembly. I put that in yesterday, and after some fussing and adjusting the tension screw, I managed to print a few little stencils without issue, but as soon as I tried the next piece of my helmet - clicking and skipping again. The most frustrating thing is that it would extrude fine during filament loading, during flow calibration, and even through the first layer, but once it starts the second layer total failure. I’ve run so many calibration cycles I’ve lost count. I took apart the heater assembly and tightened the 4 screws in back, which were a little loose, and the next print that got to the first layer looked much smoother, but then on the second layer lots of clicking and skipping. I can manually advance the filament through the PTFE tube and the skipping stops, but the machine won’t pull it through smoothly on its own. I took everything apart again to make sure things were seated properly, but no luck on printing. I ran a flow calibration through Bambu Studio and saved the specific k value for the Sunlu filament I’ve been using, thinking it might be a dynamic flow issue. The calibration extruded fine, but the next print failed on the first layer. It seems to be getting progressively worse. I don’t know if I should next try to replace the extruder motor, or check the connections in the circuit board, or just replace the circuit board. Right now it’s little more than a paper weight.
The filament is the same roll as I was using after changing the hot end, and I successfully printed several pieces before it just stopped working right. And now I can’t even get the filament loaded without it getting hung up clicking, so I’m trying to find if there’s a clog somewhere on top of whatever else is going on.
Unspool a couple meters of filament to be sure it is not tangled.
I finally solved my issue. After replacing the hotend, extruder gears, filament sensor & sensor base, AMS lite hub, PTFE tube, and filament, all without solving the issue, I replaced the toolhead circuit board and it’s printing like a brand new machine again. So I think there was a circuit fault, probably caused by heat creep. The heat shielding is practically non existent in the a1-mini, so I expect that replacing the board will likely be a regular part of maintenance on my machine.