not sure about the model or the age, but your blowr assembly is mounted either with sheet metal screws to the top or side housing with tabs or some other means, or it may be foot mounted with rubber bushings on the floor. once loose, you may have to turn 90 degrees and/or tilt to remove from the space. kill the power and disconnect the wiring. pull the assembly and take it outside. remove the motor mounting and shaft set bolt as bigwheel said and remove the motor. the blower wheel will come out after you remove one more peice which is a removable peice of the housing at the opening. once removed, you can wet down the wheel and housing, then spray with some coil cleaner. after soaking, you can then wash it with a standard hose nozzle, reassemble and reinstall. the last step in reassemble is to center the wheel on the shaft between the walls of the housing, then reset the set bolt.
your 'tech'........the one who did not do the service you are about to do......found a bad capacitor inside and outside, yet your system is still working ? makes me wonder if his meter is working. if you have or know someone who has a digital multimeter, you can check the capacitance yourself. kill the power, remove one wire off the capacitor and use the mfd setting on the meter to verify the value.
if there is any part of this process you do not feel confident you can do safely, call a (different) technician.