Holding Tank Treatments and Your Advice on Lubricants

Unless you are planning to eat out of it, water is all you need. Use plenty of it so the solids float and get pulled out when you dump.

If you are using it regularly, it won't hurt to lube it but not critical. I believe it's when it's not used regularly, that lube is more important. That allows time for things to dry out and turn crusty.