I've been using simple green for years, but only on full detail strip and cleans. Since it removes ALL lubrication residue... you want to be sure to thoroughly rinse, dry, and apply a light coating of oil back to the metal.
It was recommended through the AGI(American Gunsmithing Institute) training courses. It works very well and has caused no problems on any of my guns be it polymer, aluminum, stainless, etc. It's also non toxic and non abrasive to the hands, and doesn't smell terrible so you can use it inside.
I use RemOil after that for a light coating again. For actual lubrication points, I usually use MPro-7 or BreakFree CLP for oil - for sliding grease areas, such as on an AR BCG or 1911 rails, I'm a big fan of red axle grease(a little goes a long way).
Glock 19 G4 BFG | Glock 17 G4 FDE | S&W M&P 22 | S&W M&P 45 | S&W M&P Shield 9 | Ruger GP100 4" | Sig P226 MK25 | Sig P229 Extreme | Sig P320F | Sig P320C | HK USP 9 | HK USP 45 (Tan) | Walther PPQ 9
Daniel Defense DDM4 V4 | Arsenal SGL 21 | ASA SBR | Savage Mark II FV-SR
Mossberg 590A1 20" SP | Mossberg 500 Cruiser