If your car was stolen you would make a claim through the Comprehensive portion of your auto insurance policy. Gas or fuel that was used by the thief would not usually be covered by your insurance policy since there is no way for them to verify how much fuel the vehicle had in it when the car was stolen from you.

Cleaning of the vehicle may or may not be covered by your Comprehensive coverage; you would have to read through the terms of your policy. If your stolen vehicle was damaged than usually the repair shop that would do the work on vehicle to fix it would also detail the inside and outside of the vehicle before returning it to you.

If the car was not damaged but only driven through the mud, had things spilled inside, etc than likely the cost to get your car cleaned would be less than your deductible amount for your Comprehensive coverage and thus you would want to pay for these things on your own instead of making a claim since it would not go through for being under the deductible amount.

If the person who stole your car was caught and you had bills for cleaning your car, fuel, etc that was not paid by your insurance company you could see about taking legal action against the thief in court for repayment of the monies you are out for their criminal act of stealing your car.

To find out for certain if your specific policy would pay for your stolen vehicle's gas or for it to be cleaned after its recovery read through the terms of the policy and speak to your agent and/claims adjuster about the situation.