Need advice about soldering FC

[Gyro Doctor]

I use Kester rosin core solder in .031 D with a 66/44 blend, with a GC Electronics Digital variable iron myself.
Also have a vacuum pump driven desoldering station that I never use ... lol ... those spring-loaded solder suckers work just as well.
Have an ceramic jacketed "Iso-Tip" cordless iron too for parts really sensitive to electrostatics (like computer chips, etc).
Probably have easily a thousand bucks invested in just soldering and rework equipment in my lab at home.
Got my NASA certification in soldering back when I was building microwave communication equipment (satellites) for a lot of
military contract work at the company is was employed with.

 

[Gyro Doctor]

afraid to to use some kind of cleaner like rubbing alcohol,

Rubbing alcohol (get the at least 91% type) makes a good cleaner used with q-tips like Moz says.
An "acid brush" with the bristles clipped down to about 1/4 in. works even better for starters, followed up with a q-tip.
RA and RMA (activated rosin & mildly activated rosin) are fine for what your doing and are only very slightly corrosive if not cleaned.
Residue left between solder pads will not short anything out as far as power connections go, but it can affect high frequency device's
connections like the RX and VTX if it bridges from one pad to another. DO NOT EPOXY anything, use fingernail polish like GJH says.