For a 1990 Honda I'd start by paying $6 or so for a new key
from your Honda dealer. They will cut it precisely.

I replaced the original key for my 1991 Civic last month,
because the old one was sticking, and folks here had said
new keys make a difference. They do. Problem solved.

Hello

I have recently observed a weird behavior my car does and is happening
only in Cold when the temperature is below 20F or so... Problem occurs
only when (I have to run short errands) My 1990 Honda Civic car is not
fully warm enough.
 In this condition, when the car is not fully warm / or engine has not
been running for v.long time when put the CAR in Park mode, my Key from
the ignition does not come out.  Earlier I thought this was stuck due
to freeze and there for I purchased several liquid sprays that would
help de -freeze the key, so that it comes off easily from ignition.
But apparently I was wrong here because Key still never came off, with
Car in Park mode.
  Closer observation showed me that actually When car was brought in
Park mode the Par Light on the display never turned ON. After waiting
inside the parked Car for roughly 25min or so when Car was fully warm
enough I saw Park light turn ON and immediately Car keys from ignition
released and came off.

  Does any one know what actually is happening and what possible
symptoms my car is exhibiting

Thanks
Foz_m