What?
Please tell me you are joking? :shake:

This is probably the daftest thing I have heard since knowing of someone who superglued a CPU cooler to a CPU in a computer.
The mirror and sensor are seperate items, for the sensor, a rocket blower, sensor swabs and fluid, an artic butterfly of or a lens pens sensorklear.
Any dust on a mirror should easily be removed with a rocket blower.
It doesn't matter how soft the tootbrush is, the mirror is easily scratched and that's a dead cert to b****r it up along with the sensor.
.
A lenspen or a microfibre cloth will do for cleaning the viewfinder.
If there is still dust showing once a sensor is fully cleaned then it is probably on the focussing screen.
These can easily be removed and cleaned but be cautious as they can easily be scratched.
It's not a difficult job to do yourself, a little patience and don't rush the job.
A proffesional sensor clean will probably cost you £40-£50 and there is no guarantee that it will be 100% clean.
Swabs and fluid will cost around £10, lens pen sensorklear pen around £10 and an artic butterfly around £45.