Interesting dream. This one points to how you feel about your waking life situation. You want to make progress in life but may be unsure about how to do it. You may not see the answer (invisible). Someone cleaned it your vehicle and since you did not see who did this, you will have help in clearing things up.
However, this isn't really telling you to clean your waking life physical car. It's about how you feel about yourself. Perhaps you subconsciously believe that you aren't prepared to move forward yet because you have some reflection, thinking, making decisions, dumping some old issues, etc. (all forms of cleaning) to do first. But someone will help you so be on the look-out for helpful souls who cross your path.
When you're ready to move onward, you may be slightly delayed by some meddlesome female (a mother/aunt, someone who is a mother or plays a motherly role in the lives of others). Look for a person who pays attention to her fashion sense, femininity, health and fitness. She'll want to come along for your life ride. She is not the person who helped you clean your car.
She'll be outspoken and say unpleasant things, giving you unsolicited advice, etc. and then try to make weak apologies to "clean up" the mess she makes. She'll eventually stop and leave you to carry on.
