Left Shift not working for combination with [ I have an Apple (wired aluminum) Keyboard (using with Mac mini).

Left Shift + [ does not work (to type {). But Right Shift + [ works.

Left Shift key is working for all the other keys.

I tried this keyboard with my laptop and the behavior is same.

I assumed it is hardware problem. I tried disconnecting and cleaning from outside and shaking off dust and debris. 

What other measures should I take to correct this malfunction? or this keyboard is gonna die?

One of the other strange behavior is on USB connection, the keyboard automatically types - until I presses a key. (only on Mac Mini)
I think it was Keyboard Ghosting problem. You can read more here

The problem was solved after I have tried pressing the key combinations (involving non-working key, in my case [).

There are a lot of combinations and so I don't include it here. In case it disappeared, here is the archive version on the archive.org.