my cigar shop is telling me that they can sell me a solution of distilled water and glycol which eradicate any beetle problem, and also prevent mold. They're telling me I won't have to freeze the cigars if I use this solution.
Is this true?
Should I buy it?

Never heard of glycol having any effects good or bad on beetles... only helps regulate rH.

I guess by regulating the RH it will indirectly prevent beetles. I wouldn't rely solely on the glycol though. Keep your temp and RH down and you won't have any problems.

Hogwash! The beetles will be having PG cocktails while picnicing on your MC2s...

Urban legend my dear fellow Urban legend!

First off, it's not glycol. It's propylene glycol. Due to it's properties, this stuff tends to keep the RH dead on 70%.

flashman and sheepshead, I don't know if it really helps fight beetles, but in theory it should. It's a form of alcohol (so yeah, flashman is right to some extent regarding cocktails). Bugs shouldn't like it, bacteria shouldn't like it and mold spors shouldn't like it either.

It is not alcohol in the traditional sense.It is even used in some edible processed foods from what i have been made to understand.And the infamous smoke machines in the disco's of the 80's.

From what I understand, the PG itself is not released in the air in important quantities (not enough to make it toxic), rather, it sits in the humidifying device and absorbs humidity. It might have an effect on bacteria, but not on insects such as beetles. I'm sure many of the guys here who had beetles were using PG...