At the time I was doing this, my Macbook was really my only means of programming on the go so I had to make do. However, I will say that putting in hours and hours of runtime on a CPU running above 100 C is not the best idea.
If it is idling above 90, that's a bit different. This is all pretty normal in my book and cleaning out the fan won't do much. Sometimes when I have runaway processes and need to restart, it will get up to 80-90 without doing a lot of work. My current Macbook Pro (Retina, 13-inch, Early 2015 - 2.7 GHz Intel Core i5, 16 GB 1867 MHz DDR3 RAM) idles around 50-65 C and can get up to 100+ when I run heavy processes in Matlab. After 3 years of walltime and hundreds of years of cpu time, I'll respond to this question to update for anyone interested in modern day values.
