Our bath was fitted after the walls were tiled (before my time here),
so any water running down the tiles could and did get behind the
bath. SWMBO bought a curved plastic strip (a bit like upside down
coving) that sort of solved the problem and was stuck to tiles and
bath with some black gunky goo a bit like mastic. All very well for a
short term bodge but hardly pretty and latterly the goo has been
oozing out from behind to make it pretty unsightly. Clearly, the
right thing to do is to re-tile properly and re-position the bath, but
I'm looking for a better short term fix until we make a proper job of
the whole room.

One plan I've thought of is to add a row of border-type tiles just
around the top of the bath and seal with silicone etc. Haven't found
the right thing yet but I'm thinking that something like a quadrant-
shaped jobby should do the job. (Why doesn't anyone seem to make
proper edge tiles any more? Cost, I'm sure, but those plastic strips
are pretty naff.)

So, the questions:
Has anyone encountered this mastic-y stuff and successfully removed
it? Looks like it could be a bit of a pain to shift unless I can find
a suitable solvent (which I can't really do by trial and error before
taking the strip off).
What's the best way of getting key on the existing tiles to take the
adhesive for the new ones? Abrading the glaze seems like one option,
perhaps a little tricky to get right, but painting something on might
have some mileage.

Cheers all