Out of curiosity, which case is it?
Its pretty odd that an ac repair shop says they don't have knowledge of it
since its installed in air conditioners >_>. Either this is the choice or get it from sidewinder computers. If you want, you can try and ask in places where they install vents air conditioners for offices and business centres. In any case, this material is accessible.
FYI, you are not supposed to use vacuum cleaners on any of the hardware as it generates static. Use isopropyl alcohol with 90% alcohol content to clean the heatsinks and the thermal paste, good old fashioned non static brush and can of compressed air instead.
If you are going to follow the "oh so far I haven't had any problem when I used my vacuum cleaner so I will keep on using it" philosophy, some drugged dimwitted illiterate idiots also claim that they didn't get any diseases from drinking dirty water, eating street food, not having bath and eating raw meat. If you think about it, the philosophy and the type of people implementing it are the same