What lapping fluid should I use on the CBN honing plates when sharpening chisels and plane irons?

There is nothing that says you to have use only one thing for lapping. Use whatever you like: dish soap, hone rite, water, 3-in-1 oil, baby oil etc. Make sure your hone is thoroughly dried if you use any water. Rust caused by water left on the hone is not covered under our warranty.