Homemade descaling agent for super-automatic?

[beezus]

I have a Gaggia Synchrony Logic - for three years it has worked great. Now it will occasionally not brew (nothing comes out) and I guess I should have descaled. However, now we are living in a little town in mexico and I know I won't be able to buy descaling agent here and shipping it is out of the question. Gaggia website says vinegar is a non, is there any other home remedy until I can get some from the States?
Thanks

[HB]

Now it will occasionally not brew (nothing comes out) and I guess I should have descaled.

I know little of super-automatic espresso machine maintenance, but as I understand it, super-automatics demand careful attention to a cleaning schedule to keep their passageways unobstructed. Have you cleaned it regularly? If not, it could be clogged with coffee sludge and scale. A little searching led me to these Jura/Capresso super-auto cleaning instructions and various vendors selling cleaning tablets.

Back to your original question: Substituting cleaning powders can lead to more problems (e.g., a repair technician shared the story of someone who used dishwasher powder to backflush their Rancilio Silvia and clogged the grouphead with hard-packed crystals); vinegar can substitute in a pinch as a mild descaler, though you'll be rinsing... and rinsing... and rinsing to remove the older and smell. For that reason, the usual recommendation is citric acid, which is available from brewing supply stores and some supermarkets as "sour salt". Sorry, I cannot assure you either would work with your super-automatic.

[Everman]

You should be able to find citric acid even in your location, it's cheap and will get the job done.

[cannonfodder]

Three years?? You may be beyond the cleaning stage and in the replacement stage. Once scale gets beyond a point, it will require disassembly and professional descaling. A descale solution soak will do little when the scale is an inch thick. It takes more dramatic measures (hammer/chisel/super strong acid) to get buildup like that out.