anti squeal shims and ferodo pads. hatch brembo
 

I am fitting new ferodo pads which have an anti vibration pad glued to the back. Am i correct in assuming i dont have to refit the existing anti squeal shims. Also they are really tight fit due to the top and bottom stainless slider shims held in by screws. Would you try remove these and clean them or just file the pads down .3mm.
thanks