I have 4 batteries. 3 of them are from the Fly More combo bought in January/2018 (when I was living in NYC)

Those 3 flymore combo batteries was manufactured Oct/2017. The other Sept/2018.

All 3 fly more combo batteires was swollen - they´re about 40 cycles eatch one.

(Observation: I have seen a lot of cases of M.A. swollen batteries - make me think a production fault)

Now I am living in Brazil, and here, batteries are very expensive (about 150USD each). So to change all 3 I would expend almost 500USD.

Problably it´s not advised, but carefully, I oppened all 3 batteries (they are not glued - just docked) and punctured the cells (3) metal sleeves. Some gas out (smells funny), taped the holes and closed the batteries.

Swell is solved and the batteries are working okay.

What do you think about this? Crazyness? It´s okay? A time-bomb?

Gas is not human friendly and a timebomb. Always a risk to use modified battereis. My 2 cents

You are absolutely crazy!  There is a reason these Li batteries are swollen and just poking a hole in them to allow out gassing is the dumbest thing you can do.  Just get new batteries , dispose of the swolen ones and get on with it.  Just sayin!!!  

It is highly discouraged to use these batteries. They can refuse at any moment, the drone will fall, and then the damage will be much more than the cost of a new battery.

Hello and good day Adriano Araujo. Thank you for reaching out and for sharing these information with us. I hope that you will get the best feedback from our valued DJI co pilots with regards to this matter. Just a friendly reminder that please do not fly your drone with swollen batteries this might lead to an accident during the flight. Have a safe and a happy flying always.

Instead of a comment i just placing a link..
https://youtu.be/zHG_FEkZUsg.
DON'T MAKE EXPERIMENTS WITH LITHIUM BATTERIES.