But if they are making a creaking noise,,,, between the time you have that happening and when you get them replaced.... Muratic Acid is a proper thing to stop the squeaking noises... Some things will cause the rubber to deterioted faster... this is not one of them.....
And some rubber bushings are not in the category you mention.. like the ones isolating the torsion bars from the firewall...
Once you have movement which is causing the noise,,,then you have lost that torsional effect you are referring to .. like on A Arm bushings... and might as well keep them from making noise until replaced.... Greg