foreign currency exchange - 舊金山

Hi,
I plan to visit Hong Kong and Singapore for about 2 weeks, and
thus am thinking whether I should exchange some HKD and SGD in
San Francisco. The amount is about 1500 USD per place.
Does anyone know the best way of getting this?

Another option is to purchase the traveler's checks (I am using CitiBank),
but I am not sure how convenient it is in these two places,
and how can I exchange them to cash if necessary.
Please advise. Thank you.



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