You can try to clean it with demineralized water, then rinse with alcohol and let it dry completely. Visually inspect for any residue (it often shows as a white powdery film. If you find some, try to remove it using more demineralited water and e.g. a soft toothbrush.
Then give it a try.
You may upload a crsip foto of your remote's PCB (front and back), maybe someone here can point you into the right direction where to look for possible problems.