I HAVE A HOUSE THAT IS 27 YEARS OLD. NOTICED THE GROUT IS COMING OUT IN SOME PLACES IN THE SHOWER. GROUT TOOLS DON'T SEAM TO BE GETTING OUT THE OLD GROUT IT'S REAL HARD IN PLACES.ALSO I HAVE USED A DREMEL TOOL FOR GROUT. DOES ALL THE OLD HAVE TO COME OUT FIRST BEFORE YOU CAN REGROUT?? IF SO I NEED SOME SUGGESTION ON HOW TO GET THE OLD OUT. WE HAVE BEEN WORKING ON THIS ONE MONTH ALREADY!!!! HOME DEPOT AND LOWE'S PERSONAL IN TILE DEPT. SAYS IT SHOULD COME RIGHT OUT WITH NO PROBLEM!!