Jeep AC smells like old socks when I switch it on, what causes it?

[Codysutton]

Every time I switch on the AC in my Jeep Grand Cherokee, the first minute smells like old socks, and my wife now refuses to sit in the front on short trips. The car has about eighty thousand kilometres, and I live in Sharjah, where the car sits in the sun all day and the AC runs hard from the moment I start the engine. The air is cold enough, so at first I did not think it was a big problem. But the smell gets worse after I park for a while and restart, and last week my son said the car smells like his gym bag. That was the moment I knew I could not ignore it any more. My cousin says it is just dust and I should spray something into the vents and forget about it. A friend says the smell comes from mould or bacteria growing on the evaporator, and that a spray is only a short fix because the real problem sits deep inside the dashboard. I looked online for a Jeep AC workshop in Industrial Area 2, but every page said the same thing, so I still do not know what a proper clean includes. So I have a few simple questions for people who know more than me. Does a good shop replace the cabin filter first? I have never changed mine, and I think it may be very dirty from all the dust here. Do they clean the evaporator with a special foam or a machine, and do they have to take the dashboard apart? I heard that is a big job, so is there a cheaper way? Also, can a blocked drain make the smell worse? I noticed a small puddle under the car once, but I am not sure if that is normal. Is the smell a health risk if I ignore it, especially for my kids in the back seat? Another thing I wonder about is habits. A neighbour told me to switch off the AC a few minutes before I park and run only the fan, so the inside can dry out. Is that true, and does it really help? I also want to know how long a proper clean takes, and if I can wait at the shop or must leave the car for the day. And what should it cost on a Jeep, so I know if a quote is fair? If your Jeep had the same smell, please tell me what fixed it, how long the fix lasted, what you paid, and what you would do differently. I would also like to hear from anyone who tried a spray from a shop and found it did nothing. Easy answers help me most, because I am not a car person and I just want my family to stop complaining.