I have nothing but blued guns. My maintenance program is simple. I clean my guns as soon after shooting as possible. I use Hoppe's No. 9 (the original, yellow label that comes in the half gallon can) to clean the bore, chambers, and interior and exterior. I wipe this down, then oil. I use a 50/50 mix of motor oil and Three-In-One machine oil. I wipe it on pretty heavily, the assemble the gun and wipe it down with a blue paper shop towel that I get from AutoZone.
I get criticized for using my "formula" but its worked for me for over fifty years.