Cleaning Recommendations for Cornwalls?

Hello --

Just picked up a pair of '78 Cornwalls, surprisingly in great condition, but a great deal of dust inside (The woman I bought them from didn't know the grills were removable!). I'd like to avoid removing the back cover if possible, but it's probably not a great idea to stick a vacuum attachment inside the ports on the bottom Any ideas? I'm probably missing something obvious... Thanks in advance.

A vacuum wand probably would not hurt anything if it is inserted in the ports at the bottom of the speakers. A round brush or duster would loosen up the dust that has adhered to the surface. An old tooth brush works well in the corners. Keep the wand in the area you are brushing to keep the dust from flying around.

I have used a air compressor. I stuff a paper towel in the mid horn and put a piece of painters tape over the tweeter horn. The woofer coil is pretty well sealed.

Yet the backs come off so easy