I personally have put water in a tart burner and added a few drops of oil with no problems. If you choose to do this...I would add a warning label to the product.
ThanX for the response, Debbie. I'm not sure what the implications are for me for the first part of what you said. (Sorry!) For clarity though:
1) Is the flashpoint of each FO/EO the determining factor in whether or not they can be used with water in a tart burner? The flashpoints of the FOs I use range from 147 - 200 and EOs 108 - 135.
2) Does the IFRA max use guideline for use in Candles/Potpourri come into play here? For my FOs, most say 100%, but one reads 66.6%. There is no IFRA max in this category for the EOs, so I'm not sure where to go with that.
3) I'll go with use for dropping on potpourri or wreaths as a suggested use, and I'd also like to offer the water plus a few drops of oil idea. Would I be okay to package and sell both ways as long as I include a warning label? Or is my safest bet the no burn usage?