Could you turn it loose?

[Silverobama]

I bought many things in the supermarket but I forgot to bring my bag. I wanted to drink water because it was very hot here. I couldn't turn the lid loose because my hands were tied so I asked my friend to help me, I said to him "Could you turn the lid loose for me so that I can drink the bottled water?"

Is my question natural?

 

[emsr2d2]

BrE would use the following options:

I couldn't get the lid undone.
I couldn't unscrew the lid.
I couldn't undo the lid.

Can you get the lid off for me?
Can you undo the lid for me?
Can you loosen the lid for me?

 

[Skrej]

AmE uses 'open' for screw-top bottles.

Simply ask him "Could you open this for me?"