Pick up your brain, when can I use it?
Could this sound natural?
As you have been to Britain many times , can I pick up your brain on what the best place is for changing euros into pounds?
What bureaus de change give best rates/ less interests???
Thank you

Question

Answer

Instead you could write:
As you have been to Britain many times , can I pick (remove "up") your brain (instead of "on" use:) about* what is* the best place (remove "is") for changing euros into pounds?
Which* bureaus de change give the* best rates/ lowest* interests???

Great job though!

Answer

Yes, your use is fine.
If you leave your question open for a while, you can pick the brains of many people :)
.
Just see corrections below.