I'm aware, But actually, I changed the thermal paste about five months ago, I just checked and there's still a decent amount applied, And the fan is not too dusty.
My heatsink (If I can call it like that, It's just a lame, Lousy fan) is a bit shitty though, It's the one included with Intel processors, So it doesn't do a good job, But my case is fairly small, So instead of upgrading this PC, I might just as well sell it and build a new one, I've got other plans on my mind for now though so upgrading this old machine isn't in my top priorities.
My CPU is running at 2.6GHz, Not OC'd, The highest it can get is like 80c under load.
Also, Intel CPU thermal shutdowns are at 115c. Yeah, I reached that high sometimes due to tons of dust clogged up the heatsink.