LCD failure usually manifests itself as bleeding of the characters and/or odd black splodges.

Segments that fade in and out are usually connector problems. They will change over time and with changes in humidity and temperature. Often just loosening and tightening of the LCD frame will help (though it may sometimes makes things worse).

It is possible to remove the LCD and gently clean off the zebra strip and circuit board. You can do a 'drag wipe' on the LCD contacts: wet a folded strip of lens tissue in 90+% isopropyl alcohol and drag it across the contact area, letting the weight of the lens tissue do the cleaning. You can do several 'drag wipes' without doing damage. I have used soap and water and an ultrasonic cleaner for the zebra strip - a very light wiping with alcohol should be ok. The circuit board contacts can be cleaned with a light brush with a soft pink eraser and then isopropyl and a swab. Putting things back can be a minor nightmare: you have to get the zebra strip back in position so that it is straight across the contacts. Swiss watch-repair tweezers, miniature screwdrivers and a 10x jewelers' loupe - or something equivalent - are almost mandatory if you want better than luck odds.