In many scenarios, recycled plastic lumber can be worked like hardwood, however it is worth noting that it should never be cut lengthwise.  This is to do with differing tensions between the “skin” of the recycled plastic and the inside. Nor should deep notches over 50% of the width of the plank be cut into it.  Cutting a notch into a lumber plank weakens it as would be the case with timber.  Therefore if notched planks are integral to your design, we suggest this is only as part of a finished product which remains static, ie. not something which is regularly moved or dismantled.