Precision M4300 Cooling Issue

I have an M4300 (3 yrs old) which had started to run mildly hot (it steady states at about 44-46C with the fan running at 3500rpm while docked and returning to minimal load after moderate to high usage). I went and bought a can of compressed air and simply blew it into the bottom and 2 side vents.

The difference I observed was surprisingly significant. Under the same conditions as above, the M4300 now operates at about 35-36C with the fan running at about 2900-3000 rpm.

However, after looking at some articles on the web, I have several questions:

1. Most cleaning advice had the user doing some disassembly in order to access the fan - it was then pointed out that one should keep the fan from rotating as the compressed air was applied in order to avoid damage. Since I did not take anything apart and simply applied the compressed air through the vents, was I in danger of damaging the fan?

2. Again, since the laptop was not disassembled, where did all the dislodged "crud" go - and if it remained in the case, how much of a problem would this be?

I would like to continue this "preventative" use of the compressed air on a monthly basis (recommended by a Dell-provided service tech) without having to take apart the laptop, but am now wondering about any potential damages that may result.

Thanks,
Harvey

 

1) I always hear people warning that you can damage the fan by spinning it up beyond it's rated RPM... but I honestly don't think this happens much. I've put a lot of compressed air through a lot of fans, and I haven't actually broken one.

2) If none of the crud came out of the machine, then it's still in there. There's no real danger of the crud directly harming your machine, but it'll probably start building up again real fast, and your cleaning will have been for naught.