Old HKD are they still Valid to use?

A question about : Old HKD are they still Valid to use?

I have just exchange currency to HKD from kanoo currency and found some old Late 80s 10$ and 50$ Notes in the pack.
Are they still Valid to use in HK?

Best answers:

• the 1980s notes ( 50s purple with 2 lions on back 100s red same ) are outmoded notes , i would get onto where you got them from as its there mistake
  possibly exchange them at a bank when you get there probably be Hong Kong & Shanghai Banking corporation