My on-line checking of the term "Rinsate" did not provide a clear answer - generally the dictionaries didn't list it. What do others here think?
Here is how I use it: Rinsate - the effluent from the process of rinsing a container; often containing contaminates. For example, the used gallon jug of pesticide needs to be triple-rinsed and the rinsate collected for proper disposal.
It is a new word to me. As a technical term, it's not surprising that it might not be found in common dictionaries. I googled it, and found it in a lot of government and education sites and publications. I would consider these sources to be credible.
A search of Google books shows the term used in a number of technical publications:
rinsate
I think you have a winner.
Stephen said
often containing contaminates
I have never seen contaminates used as a noun before.
I think contaminant would be more standard as the noun form. But I can see how, in the context of lots of nominalized words ending in -ate -- nouns that are the product of a process (see 3. below) -- that contaminate (noun) might pop up from time to time. It could help distinguish between something that contaminates something else, as a source of contamination, the contaminant: "Hydrocarbons are the primary contaminant in this lake.", versus the final product of contamination, the contaminate (noun), e.g. the lake water, now contaminated by hydrocarbons.
-ate
...
2. forming nouns a chemical compound, esp a salt or ester of an acid ⇒ "carbonate", "stearate"
3. forming nouns the product of a process ⇒ "condensate"
I agree that it's useful distinction; I've just never encountered it.