Three years isn't that long for a ceiling fan to start failing just from getting old, so there's almost definitely something more than dust behind that squealing. That high-pitched noise typically comes from the bearings that are drying out, and while accumulated dust definitely doesn't help, cleaning just the blades often doesn't fix the actual problem.
Here's what others might not mention: if the squealing is coming from the motor itself (and not from friction between the blades and the housing), cleaning the blades on the outside won't do anything. What you need is to lubricate the internal bearings, and that does require taking the fan down. Most models have an access point (usually a small cap or hole in the center of the motor), but some are sealed from the factory and then there's no clean solution. Another risk: if you try to clean it thoroughly without taking it down, the dust falls right on you and can also get deeper into the motor if you're not careful.
My recommendation is to take it down. Reinstalling it is quick if you did the first installation right - takes about twenty minutes. Once it's down, you empty out the dust, check that the blade screws are tight (they often come loose and cause vibrations), and if it's still making noise, apply a little light oil to the bearings. If it keeps squealing after that, then it probably needs new bearings, but at least you'll have ruled out what's most likely.