Keep using finer grades of sandpaper. Use the wet-dry sandpaper and sand with plenty of water. After each phase of sanding go to a finer grit and continue with more wet sanding. Keep going, using finer grit with each phase. After sanding use a polish to buff out the tiny scratches. Then wash with dish washing liquid and rinse with plenty of water. Let air dry and check your work. You may have to go back over with more polish to eliminate the small scratches.
Berny
Phormer Phantom Phixer
On the bench
TF-102A Delta Dagger, 32nd FIS, 54-1370, 1/48 scale. Monogram Pro Modeler with C&H conversion.
Revell F-4E Phantom II 33rd TFW, 58th TFS, 69-260, 1/32 scale.
Tamiya F-4D Phantom II, 13th TFS, 66-8711, 1/32 scale. F-4 Phantom Group Build.