Two cycle engines have there oil mixed in the fuel and the snot is just spent used oil. That lubricates the engine and helps keep it cool. Get used to the mess and stink if you are going to fly glow engines. That is just one of the reasons electric power is becoming so popular today. I live in a little town right outside of Las Vegas NV and yes, it gets hot here but this time of year is about perfect. It was maybe 70 or 75 when we left the field today. Being a desert it can also snow and gets into the 20s but during the summer it can and will get to about 115 and more. About 100 to 105 is normal in the summer.
Today was electric plane day so it was just fly and put them back in the van when we were finished. Yesterday it was gas and glow day so I was cleaning engine snot from my planes. Gas power is very clean, none of that nasty oil all over the planes, glow power is pretty nasty but too much fun to not use.
Anyway, sounds like you have a pretty good handle on this flying stuff, have fun with it and welcome to RCU!