Hello,
ITC of inputs, input services and capital goods used specifically for selling lubricants will be available and can be utilized against the output tax liability of lubricants.
While ITC inputs, input services, and capital goods used for both Non-GST and GST supplies will be available proportionately.
So you need to reverse only the proportionate credit with interest.
I hope that this answer satisfies your requirement.
Regards,
CA Hunny Badlani