Your family members using your cars.

Okay those of you who know me a little know that I'm not scared to stand on my soapbox from time to time.
Now don't get me wrong because I do love my wife and 18 year old son but. 

My son has a car of his own and choice but he keeps on asking to use my Cabby, like yesterday because the weather was very nice indeed. 
So he had it for the afternoon and evening, yes it did come back in one piece however he uses the Fuel without offering to replace it. Plus it came back heavier than when he left. 
Roughly speaking he added 1lb of dead flies which I've just spent an hour removing at the cost of €5 at my local garage that has a steam cleaner. 

Now the Mk6 estate. 
My wife and son as above really, they use the car but have no idea how to remove the Fuel cap or anything else come to that. 

So I'll try to sum up here and hopefully the forum members have some ideas that I might try to change the way they feel about using free cars.  👍 

I've paid for both cars. 
I pay the car insurance on the both which is horrendously expensive here in Austria. 
I pay for or do every piece of maintenance on both cars. Not much on the 6 to be honest. 
MOT's, tires, oil, washer fluid, you name it.
I clean both inside and out, just finished the Mk1 and I will take that home jump in the Mk6 so that I can tank and wash that as well, oh by the way I cleaned the inside of that yesterday because my son had the Cabby so I couldn't do that one! 

So don't hold back, tell me please how you'd feel in my shoes? 
Maybe I just am a bit old fashioned and was taught different values!

If I borrowed my mothers car, which I have had to do in the past for various reasons, I give her petrol money or fill it up, especially if I'm travelling further than 10 miles.. Tbf she always seems to run her car around on a fiver and it drives me nuts!
I agree with you, if I had half a tank and someone borrowed my car, returning it on red I would ask them to replace the 30quid of petrol they clearly guzzled. 

But… I am bitter, I trust no one and so no one's allowed to drive my car… Xx

You know I've been thinking about this and I'm more disappointed that neither of them offer to do anything for the cars Full stop.

My son is not stupid when it comes to cars and my wife is no mug either but they seem to think that doing anything I listed above would constitute a criminal offense or at the very least they'd contract Mad Cow Or Bird Flu!

Even the the washer bottles are radioactive.  

Maybe you need to invest in a "driving n larks" fund…put a money box or tub in the centre with a note saying please replace what you use… Or you might have to start putting your foot down and say if you use the car fill it up so everyone can enjoy it. You don't need to have a go, just sometimes if you don't speak up people assume that their behaviour and attitude is appropriate and causing no harm. You gotta stand your ground. You pay for everything on the cars, it's not unreasonable for you to ask that if anyone else wants to use them they contribute to the running costs or pay fpr a valet or something.
X

Like ya thinking Kirsty!    

Good luck laa! X they probably don't even realise they are doing it!

Maybe you've just too much money Mike , or so they think 🤔🤔
Not a nice thing IMO especially your being God enough to lend your prize possession , don't think I'd be so accomadating 
Just man  up tell them if ya gon a use it (especially a mk1 ) get your hand in your pocket !!!!  Simple as …. 

Lol I have the same issue which really drives me mad when I go to drive the car and its on red, so now I just hide my keys, like your situation they have their own cars, hide the keys no one would drive it, and your not doing any harm as you mentioned they do have their own cars,