She uses it primarily to clean the underdeck of the riding mower and to clean my grill grates and drip pans.
Your wife cleans the lawn mower??? Good for you. 
Well, she is the one who uses it so she also cleans it.
To be fair, we reached an agreement years ago. When we decided she was not going to work for a living anymore, the rules were she became in charge of all household maintenance. I buy her the very good equipment to make the job easier and she takes (almost) good care of it. I cook almost all proteins. I provide all of our income and ensure she gets to put the max in her IRA every year. It works for us, but may not work for every marriage.
