I have just bought a Ford Ka (small UK car) that has done only 1500
miles even though it is just over a year old.  The car has a rough
surface which appears to be simply because the owner did not wash it!
I have tried warm and hottish washes but to no avail. There are very
small black particles all over the car that can only be seen close up
- I do not think they are anything sinister and are not tar. Rubbing
hard with a paint restorer "can" remove the roughness but I am
concerned that this may damage the paintwork as it may need 2 attempts
(wihich is alos very hard work).  Can you offer any advice as to how
to remove it more easily?