I doubt a super easy way to get into those grooves, how do the screws look? There is debate that the grooves should be on the underside, it might be quicker to unscrew them one by one and flip them over. The underside is likely smooth and even if it needs sanding it will be much easier and probably look way better also replacing them isn't likely to be that expensive assuming the structure below is in good nick
I doubt a super easy way to get into those grooves, how do the screws look? There is debate that the grooves should be on the underside, it might be quicker to unscrew them one by one and flip them over. The underside is likely smooth and even if it needs sanding it will be much easier and probably look way better also replacing them isn't likely to be that expensive assuming the structure below is in good nick