Cleaning and dust removal from the mono 250 Ref.
 

I think it's time to proceed to a thorough cleaning of my mono REF 250. I have found no literature about it and one thing is certain, I will absolutely not use compressed air cans.
I only intend to remove the dust and therefore I turn to you who certainly know more and have a lot of experience: how can I clean the inside of these beautiful machines? Thank you.

If you are against compressed air (not sure why?), low psi isn't harmful then how about a bulb syringe blower used to clean sensor plates in cameras?

Use a small computer keyboard vacuum.

compressed air I mean the one in spray cans because it contains substances that enrich the air with humidity and therefore no. are indicated. the compressed air of the electric compressor is very different, I could use it

Compressed air from compressors contains oil from the compressor itself and dirt and moisture from the air it ‘breathes’. That is unless you use an oil-less compressor or one that has an air/oil separator built in. You still have the problem of dust and dirt unless the compressor has a built in HEPA filter.

Some types of Canned ‘air’ use a fluorocarbon - it is very clean and dry.

hair blower?

Dust is a real issue with AR ;every month I have to unscrew top cages on mono blocks and blow the dust away, I suspect Tubes attract dust particles.

Go to your local drugstore - CVS or Walgreens - and head for the cosmetics section. Look for cometic brushes, used to apply and smooth various facial cosmetics. They have very soft, bushy, dense bristles and come in a variety of sizes. I find them very handy for dusting audio components, especially turntables and ARC faceplates with recessed toggle switches, etc. The right sized ones could work very well inside the chassis of a tube amp.

Right on. I’ve used them for many years. Work perfectly and do no damage due to the ultra soft bristles. I use them in and on my Ref 40 all the time.

...but fluorocarbon is banned from the trade.