My first reaction is to support kchriste's recommendation. If it ain't broke, don't fix it. Brush it and vacuum it and let it be. Actually, despite the fact that I've used a mil surplus dental compressor with regenerative dessicant dryer for cleaning things for many years, you are better off using a 1" paintbrush with a vacuum equipped with a narrow sofa cushion wand, rather than compressed air. Less chance of driving dust and grit into places you don't want it like between the variable capacitor plates or into the exposed, greased ball bearings of the capacitor rotor.
My second reaction is to not use any solvents like alcohol. Decades ago, when Tektronix still made tube-type oscilloscopes (and when it was a unique company with very helpful field reps and tech support), they issued an application note on cleaning old tube-type oscilloscopes. They strongly recommended against any solvents and recommended instead a water bath with detergent! I've used that approach many times over the decades with good success.
The procedure is to protect all parts that could be damaged by water, including transformers and cardboard casings on capacitors by removal or by covering with plastic baggies, shower the instrument with detergent solution, brush gently with a paintbrush to loosen crap, rinse with tap water, RINSE FINALLY WITH DISTILLED WATER (not de-ionized water), and dry in a well-controlled oven for a LONG time at very low heat. If it is uncomfortable to put your hand on the instrument for a long time it is too hot. That's about 140 degrees F. The distilled water will leave no residue or minerals as can tap water.
Once the cardboard capacitor casings are protected or removed, the instruments are not very sensitive to water. Oh, yeah. Remove any speakers.
One big advantage is that detergent solution is less likely to remove identifying marks from components although it CAN remove identifying numbers from some tubes, so always write down the tube types and their locations. It is actually best to remove the tubes one at a time, write down their type and location in the instrument, clean them individually and put them aside in a manner that preserves their information.
Detergent solution is also much more environmentally benign and harmless to you than solvents and is available in large quantities for pennies rather than in 1/2 pints for dollars. You can use it liberally without concern. Tektronix recommended a lab glassware cleaning detergent, probably because it would rense easily and not leave a residue. I have used detergents from home supply houses like HD with success.
Solvents will effectively remove grease from the ball bearings on variable capacitors. That's not good. Mild detergent is less likely to remove the grease unless you focus your brushing on it. In either case, regrease the bearings after any cleaning procedure.
I generally put the instrument out in the warm sun for a few days rather than in an oven - largely because my wife would look askance at my putting an electronic instrument in the oven for days, but also because I have witnessed the complete roasting of a device in an industrial oven that was supposed to be well-controlled with commercial temperature controls. (That was a steel-rubber-steel sandwich railroad track fastener. the stiffness testing of which I was supposed to witness at a university test lab after it had been subjected to temperature cycling for a week in an industrial oven. When I got to the test lab they showed me a stinking mass of melted and burned rubber and steel and said to come back in a month. So I don't trust "temperature-controlled" ovens any more.)
whatever method you use, take detailed pictures and write down identifying marks before cleaning with solvents of any type.
Transformers aren't uniquely sensitive to water but they can get saturated with water within the windings and they can be difficult to rinse effectively and to dry out. That's one reason to continue the drying under gentle heat for much longer than you think is necessary by surface inspection. It's better to avoid saturating transformers with a baggie.
Good luck.
awright