I've been using WD-40 on plastic for years and never had a problem, i.e. to clean labels off covers, baked on toner. And what I've been doing lately...
Like the others said the cyan developer dumped. Make sure "any" over life consumables are replaced as well or it will dump again. It can be any other...
Been rebuilding the drum units with new drum,blade, sawtooth, grids & chips for over 2 years now with great success! Only had 2 fail out of hundreds...