There is a rubber grommet through which an elbow
passes on top of  the valve cover.  The elbow then
connects via hose to the air cleaner.  I want to replace
the stock air cleaner and place a breather in the valve cover.
The problem being the old grommet is very hard and not
removable without a chisel.
Is there any way to soften the grommet for easier removal?
I don't want to remove the valve cover if I don't need to.
Have heard to apply paint thinner to the grommet as this
will soften it.  Any ideas?

mike