This works a treat but just take care. I ran a sharp knife around the groove to get rid of some of the accumulated dirt first and this seemed to make it easy to get the knife in. Start in the middle and work carefully upwards and downwards. Do both sides before you try the ends. The only tricky bit is springing it out at the end but it seems quite robust. You have to unclip the circuit board and slide it out but this is OK. Don't break the clips and watch out for the coiled battery terminals. Make sure you dry thoroughly before refitting. I used super absorbing kitchen roll. Locate all the parts back as they were and push fit. It took about half an hour with drying but it works better than ever.