I think it's ok kahit ligh pressure...
so first, cotton buds pang spread lang ng cleaner wax
tapos, get a chopstick (e2 ung gamit ni sir edwin and i like this better than bbq... pero preference ko lang

) carve the slimmer end so make it look like a chisel (parang ung end point ng stabilo na high lighter, flat point), you can use a cutter for this
tapos make the edge dull, taktak mo sa glass or any smooth surface para maging brush like ung dulo
voila! may world class "Detailing Stick" ka na... even with light pressure, it won't scratch kc mejo brush like ung dulo..
super meticoulous and degriming, i dont recommend doing this when you detail you whole car... better to save a session just to degrime.
recommendation ni sir PSI, invite your frnds over, have a beer, and mag degrime ka... mahaba-habang kwentuhan yun!
*migs those pics give me a flashback of my first ever detailin EB... hope I can join the next ones...