Apple BT keyboard does not connect to Macs (any way to reset?)

[YS2003]

I have been trying to pair this Apple BT keyboard with my Macs. I have 2 other BT keyboards and they pair with my PB/iBook perfectly. But, this one Apple BT does not pair with any of my Macs. It pairs up briefly with PB but lost its connection.
Is there a way to "reset" the BT keyboard? My Macs (PB/iBook/MBP) all see this BT keyboard (it already has a name) but cannot pair with it.
Edit: The battery is in good condition. I even tried it with brand new batteries just to eliminate this factor as the potential culprit.

[Reflow]

I have been trying to pair this Apple BT keyboard with my Macs. I have 2 other BT keyboards and they pair with my PB/iBook perfectly. But, this one Apple BT does not pair with any of my Macs. It pairs up briefly with PB but lost its connection.
Is there a way to "reset" the BT keyboard? My Macs (PB/iBook/MBP) all see this BT keyboard (it already has a name) but cannot pair with it.

I know this is a dumb question but did you replace the batteries.

[YS2003]

I know this is a dumb question but did you replace the batteries.
Battery is okay. I know this is nothing to do with battery.
I just noticed I may need to delete the pairing with my other Mac. Maybe that is the reason I still see the name of this BT when I attempt to pair it with my MBP.

[Peterkro]

Make sure the batteries have good connections (roll them round a few times to clean contact with spring.I just had that problem with a brand new BT keyboard and it flummoxed me for a while.(RIP first BT keyboard died in action due to flood)
PS I dismantled the first keyboard to try and effect a repair (couldn't because of damage to printed circuit[ I haven't given up as soon as I lay hands on a conductive pen I'll redraw the bastards])anyway I was surprised how well they're build a regular design and engineering masterclass,compared to top of the line Microsoft keyboards it's genius.

[IJ Reilly]

I find that sometimes turning the power switch off and then back on helps with pairing problems.

[YS2003]

Finally I was able to pair this BT keyboard with my MBP. What I did was I took the battery out from the keyboard and leave it as that for about 15 to 30 minutes. I thought the keyboard is still remembering the previous pairing with my other Mac. It seems this "reset (for the lack of the better word)" the keyboard and pairing was complete.