Hello, I am sorry to hear that Tuscan got into something he should not have and ingested it. Petroleum based products are mucous membrane and gastrointestinal irritants.
It is dangerous to induce vomiting with a petroleum based product because vomiting can lead to aspiration of the product which would cause a horrible pneumonia. As well petroleum products are irritants and we would only further burn/irritate his esophagus. Never induce vomiting with ingestion of a petroleum product.
At this point we want to ease his stomach and gastrointestinal irritation. I recommend giving him a cup of milk to drink to coat his esophagus and stomach. Repeat in 1 hour. I don't usually recommend milk in dogs as many are lactose intolerant and that can lead to diarrhea but it is the best thing you have at home to coat an irritated gastrointestinal tract.
To try and settle his stomach today you can try either:1) Pepcid-ac (famotidine) at one 10mg tablet per 20 to 40 pounds of body weightevery 12 hours.OR 2) Prilosec (omeprazole) at one 10mg tablet per 20 to 40 pounds of body weight every 24 hours.These will reduce stomach acid and should help settle his stomach. These can be used for several days as necessary as they are quite safe.
Then feed a homemade diet of 1/3 boiled hamburger or white, skinless chicken, all fats and juices drained and 2/3 white rice. Add 2 tablespoons of canned pumpkin, not pie filling, just pumpkin, to each meal for fiber if he has any mucousy diarrhea. Feed small meals several times a day.
Once he's feeling better then start mixing in his regular food, adding a little more regular and less bland at each meal. It should take a week to get him converted back to regular food.
If he is vomiting, refuses to eat or is lethargic then he should be seen by a veterinarian on an emergency basis for in hospital treatment.Let me know if you have any questions.