If you have the old style (rubber) remote key head and the pads have worn down and look awful...you can replace them with rubber replacement button pads that can be found on eBay. Mine came from a vendor in China and only cost approx $6 (shipped to the USA)...and it give your old worn out key an nice refreshed look.

Below are a few images that detail the process of removing the old & installing the new pads...and you can also see the difference between the latest rubber pads I just purchased versus ones I replaced on my 99 e39's key back in 2008. It took me a bit longer this time...but that's because I took about 30 images...here's a few of them:


On bottom: new pad/ 97 e38 key
On top: old pad/ 99 e39 key w/rubber replacement pad done in 2008


97 e38 key & new replacement pad


new pad vs old pad


rear of new pad & old pad


old pad on top of new pad to mark where to excise the protuberance that covers the red LED


cutting off the fake LED protuberance


fake LED removed successfully


back of key removed & removing battery & circuit board in one piece


innards all removed & nickel placed on battery to keep programming intact...NOTE that the transponder/chip remains in its little corner


start prying/loosening up the edges of the OLD rubber pads from inside the key which are lightly adhered to the key case...be gentle & careful


then gently press/push the rubber pads thru the holes from OUTSIDE the key...careful not to break off a small ridge/ring of plastic supports that keep the edges of the rubber pads from being pushed back inside the key case under normal use of the buttons


You can see the ridge/ring supports that surrounds each hole...be CAREFUL not to cut thru or break these tiny pieces off
-

prepare to start inserting the NEW rubber pads...you can see the LIP that goes above the tiny supports and outer rim of the holes


push new rubber pad thru hole and align...don't be TOO rough because you don't want to RIP the thin rubber lip of the new rubber pads...but you can careful adjust the pad so that it lines up correctly in the holes
-

adjusting the last button from inside...there's preformed indentations that fits a small flat head screwdriver perfectly


all done...NOTE that the transponder/chip is STILL sitting in it's original location


just needs a few more adjustments...but old 97 e38 key with new pads installed...with old rubber key pad buttons removed


Gotta get back to work...lunch break is over...but here's the comparison of the NEW replacement key pads vs the one I purchased in 2008. The new pads have the arrow on the UNLOCK button pointing in the correct position. The older replacement pad (from 2008) has the arrow pointing away from the key blade in the direction of keys that use the 433 MHz radio frequency (which is used in Europe). In North America...the arrow should point TOWARDS the key blade which indicates that the key uses the 315 MHz radio frequency.


433 MHz/Europe vs 315 MHz/USA & Canada