the method im mentioning is basically going to damage the bottom section of the coil pack. its rare youll be able to save the boot section.
the coil packs are a 2 piece unit. the bottom long stem rubber section and the square top.
remove the top. they come of with some persuasion. its like a boot. once off you take out the inner spring.
add in some wd40 and let sit for a few mins. work on the next.
go back at the end of the row.
use a long skinny pick with a small blunt tip.
push down the hole with wd40 oil.
go up and down, all around the spark plug on the inside of the boot.
after a nice go around youll be able to pull up the boot.
the boot can be damaged as you should be able to buy a new set but keep the top coil pack to reuse.