Here is my detailed response in another thread on the same topic:
Yes I have. And the experience is phenomenal. Its called Hydrogen Cleaning. The procedure takes 30-40 minutes and the results are very obvious and palpable.
The good thing is that they use an alkaline liquid that is directly pumped into the exhaust pipe and leaves through the silencer exit with no residue.
For those of you in Lahore, I highly recommend Motor Clean on Walton Road. The owner Shahzad (03214002969) is a an engineer who is one of the pioneers of Hydrogen Cleaning in Pakistan.
He is a very knowledgeable and friendly guy who walks you through the whole procedure.
Unfortunately, our fuel is literally crap and thus the Cat needs cleaning much much earlier than recommended. The problem with conventional cleaning is that they use corrosive acids that can only be done once or twice max (as it takes off a layer off the cat and renders it useless). Whereas hydrogen cleaning in non-invasive and non-corrosive.
I remember that I spent over an hour with Shahzad just understanding the process before getting it done the first time. He calmly explained everything to me at length before actually recommending the procedure. Its not very costly either and can easily be done after every 20-25k mileage.
Below is a link to their FB Page:
https://web.facebook.com/motorcleanpakistan/
If you do go to Shahzad you may give him my reference. I am positive you will get a discount as well.
Hope this helps.