Manny, I've used a . . .
commerical brand called, Leak Sealer Pro made by ClipLight. Check my page (click 'www' icon below) and select Menu #16.
My evaporator had a small leak (?) and it did fix it.
Of course, there are many cons for not using it!. Buy when the cost of the repair starts to approach the value of the car, I think that would be a reasonable reason to use it.
But it should be done carefully and not hap-hazardly. The articles in the previous threads give all of the facts that should be considered before it's use.
Regards . . . . JimF
'94 S500 Cpe
Visit my Mercedes Web Page