We like the tiles in the kitchen and bath but feel that they need an accent. Is there a tool I can get that will enable me to cut a 4" channel off the tiles that are on the walls while leaving the surrounding tile intact? thanks Allen

I have a fiberglass tub with tile on the walls surrounding it. At the joint where the top of the tub and the bottom of the tile meet it has been sealed with what I can only describe as a putty. It is definitely not grout nor does it seem to be silicon caulk. The sealant was cracked on one end of the tub, so I have cleaned it out and would like to reseal. The seems on the other two sides of the tub are intact and holding up well, I would like the third side to match but am unsure of what they used originally. It is a dark brown color and matches the color of the grout. I used a putty knife to clean it out and while the surface was fairly hard it is kind of soft and crumbly when you dig into it. Any ideas what it is? If nothing else, does anyone know who makes a good bathroom caulk in a dark brown color? I hope my description makes sense. Thanks for your help!