Picked up a nice clean 1991a1 Colt with a kind of park looking finish 2698xxx number , I wanted to maybe change the Black Colt grips and clean under them , they all came out but the top left side , The screw slot is a little wide I have diff bit for them but I can put replacement screw in . any idea before I go to far . I touched the slot up with cold blue and its hard to tell was messed with ??????

Usually when you get a tight screw attempting removal often also unscrews the grip screw bushing from the frame.
Unless you have the correct tool to grip the bushing without damaging the threads, removal of the screw from the bushing will damage the bushing threads.  
DON'T try to reuse the damaged bushing.  That risks damaging the threads in the frame.

One thing to try is to put a drop of Kroil on the end of the grip screw inside the magazine well and allow it to soak in overnight.  Then but a bit in the screw slot and give the handle a fast turning "snap" to attempt to break the screw loose.
If the bushing does unscrew with the grip screw, the easiest way to deal with it is to just grab the bushing with Vise-Grips and remove the grip screw.
Then buy a new bushing and use Loctite Red to bond the new bushing in place.

When installing or removing bushing be sure to use a special bushing driver NOT a screwdriver.  The bushing driver surrounds the bushing and supports and protects it.
You can buy a new bushing and the driver tool from Brownell's.

Thanks I will check into this .

triaxle, if your bushing comes out and you have to bugger it up with vise grips to separate the screw give me a shout.

I had this problem this summer and bought a 4 pack of inexpensive bushings from Brownell's.  So l have 3 left.

I'll drop one in the mail gratis if you want it.

Or Brownell's sells bushings singly in different price ranges of you want to go that way.

I'll admit l used a hollow ground driver rather than a proper bushing wrench but l did Loctite it with moderate pressure without any problems.  Well, installing.  We'll see next time l remove the grips.

I will let you guys know , I did the Kroll oil thing in and out , I will try again tonight .

I came back home today and took the Colt out in the garage , gave a little tap and gave it a try and it came right out . Thanks for the input , I think the Krol worked . I put a set of Ed Brown screws in and put a little newer fact Colt set of grips on it .

The frame to bushing threads are 0.2360-60 NS-2 threads.
They are only .0205 deep (nominal).

If the bushing was staked removing it can easily damage the frame threads.

The frame is not all that hard in that area either.

I've had bushings come out with grip screws before; I clean the bushing hole and bushing, put some blue loc-tite on it, and screw it back into the frame. The next day I come back and try to remove the screw from the bushing again. So far, 4/4 times, the screw came out of the bushing and the bushing stayed loctited tight in the gun.

It takes an extra day or so, but it seems to work for me...