Fortunately, a lot of door, window and other rubbers are for sale simply or with a little effort. And that can be useful if a car has passed the three or four crosses.
But some rubbers are really unavailable. The rubbers under handles and trunk lock plates for example.
Machining such rubbers in relief is often made very difficult because rubber is rather soft and therefore less pleasant to machine.
Now rubber is just like water: when it gets colder, it gets harder. Rubber that has been in the freezer for a while is therefore hard. With quick calmness, that rubber can then be worked well with a Stanley knife, a gouge or a Dremel. Drilling is also possible.
A few intermediate freezing sessions may be required before the result is satisfactory. But it is possible.
And that is nice.