Interiour plastics cleaner/colour restorer?

Question for those that have had to do some serious interior cleaning, or valeters.

The wife's sister has just given here an older Vauxhall Astra as a learner car, ......BUT its been used to transport a dog and has hardly ever been cleaned, add to that she was a smoker, so you can imagine the state of it.

She has given it all a good repeated scrub, i removed the seats as well, but the plastics are still ingrained with dirt despite repeated tries, the same goes for the seats and carpets, stain's etc.

So i wanted to ask if anyone could suggest a cleaner colour restorer to get the plastic back to black/grey black, and something that will shift the stubborn stains, that's not going to cost the silly money that some of the valeting products command?

look on e bay for a chemical called viro sol its a citrus degreaser , ive used it for years on everything i clean , tobacco it cleans it with ease , tough stains on seats and carpets the same , as for the plastics if they arnt very good colour wise then apart from re painting them with say a plastic paint then they will be the same only clean if you see what i mean.

plus its dilutable and not expensive.

or if you have a clover chemical supplier near you janitorial supplies , its called citra safe , same stuff

the rest is a lot of patience

I use Autosmart G101 to clean and buy from a local Autosmart rep, then use Poorboys natural look vinyl dressing.

Made my RRC's door mouldings and dash look like new

Thanks fellas, will have a look at these suggestions and see how i get on.