yes this can be corrected if you can open up the front face of the amp.This problem is generally due to dust and carbon deposits as you have already suspected.First remove power cord and then the top cover,now look for all the screws that hold up the front face of the avr to the main chasis.There could be screws on all four sides of the face and please be sure that you have unscrewed them all. Now once the front face is off there could be a few plastic buttons covering the original micro switches which you have to clean . These plastic buttons can again have screws , remove them all and be sure to note what screws belong to which part. Now u need some synthetic paint thinner which can be bought from any hardware shop , dip a cotton bud into this thinner and apply on all the malfunctioning switches , the quantity of the thinner used on each switch should be around 4 to 5 drops , keep pressing each button as you are cleaning it .After you are done with cleaning wait for 5 to 10 mins so that the thinner evaporates by itself .Now put everything back i mean the front face and all the screws etc . Wait again for half an hour or so and then switch back your avr.
there you go all the switches should have been brought back to life
now smile and consider your self a hero , you did a great job
.... you have saved your amp from getting into bigger trouble because all these little switches could have given birth to major problems with time even a bricked amp and also you have saved yourself some of the biggest red shiny currency notes(you must have guessed by now which ones i am talking about)
and one thing more go for this self service process only if you have an out of warranty avr
finally if any of the buttons are still not working then that has not been properly cleaned up or it needs to be replaced and you should seek professional help
let me know how things went
