I dont think there will be a safe way in any kind of gambling, may be you can give us some proof that you really have a solid strategy in gambling, I
never found a really solid strategy except on martingale, even though martingale is good but it never had a good ending
well proof isnt possible as my income stays on my balance ,that i can witdraw it anytime ,but well its safe and isnt gambling.My advice is never invest more than can afford to loose ,soo this way i had invested and well the returning is coming very fast ,i cant share my vision or where my money is invested otherwise anybody would be able to use it and maybe became harder to make a good income.about double money well isnt in the short time is medium time .
So if it is not a gambling what it is then? There is no other safer method to get easy bitcoin like that. Your saying is this bitcoin is an easy money to get and it is perfectly safe, I dont think there will be any safest method in this entire world