The driver of a convertible BMW had paint stripper thrown in his eye while sitting in his car with the roof down.
Steven Dennett hurled the fluid, which went into James Halligan's face, in a "terrifying" attack outside the victim's parents' home.
A court heard the "industrial strength" Paramose paint stripper - not available to the general public - was in a tin "marked with a skull and crossbones", with warnings about the dangers if it came into contact with skin.
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When it hit Mr Halligan he "screamed" and the victim said his eyes and face were "burning", while a neighbour said they could see the leather seats "bubbling" only minutes later.
A judge today said "mercifully" Mr Halligan didn't suffer "dreadful" injuries, as he jailed Dennett for 20 months for the "cowardly" attack.
Liverpool Crown Court was told there had been "ill will" between Dennett and Mr Halligan, which "came to a head" at around 5pm, on July 21 last year.
Damian Nolan, prosecuting, said the victim was sitting in his stationary BMW, near his parent's home in Tilston Avenue, Latchford, Warrington.
The attacker drove up in a Citroen Berlingo van, slowed down next to the BMW, and "sluiced" the victim and car with the corrosive fluid.
Dennett, 40, of Adamson Close, Latchford, Warrington, admitted criminal damage and assault causing actual bodily harm ahead of a trial.
But he denied attempting to cause grievous bodily harm with intent to cause grievous bodily harm and was found not guilty by a jury.
Prosecution and defence barristers today addressed the court ahead of sentencing on whether the attack was "reckless".
Mr Nolan argued it wasn't "opportunistic or impulsive", which he said Dennett had conceded when giving evidence.
He said there was a "not insignificant degree of planning", as Dennett was driving home with a colleague when he spotted Mr Halligan's BMW, unoccupied, outside the victim's parent's address.
The prosecutor said Dennett dropped off his colleague, went home, got the paint stripper tin out of his van, then poured the liquid into a "vessel".
Mr Nolan said Dennett referred to "a McDonald's sized coffee cup", but he argued this wouldn't have held the amount of liquid that damaged the car.
He said Dennett then drove back to Tilston Avenue, saw Mr Halligan now sitting in the car, drove up and from an "arm's length" away, hurled the liquid.
Mr Nolan said: "The verdict means the jury could not be sure he intended really serious harm. The crown would submit that verdict does not mean the jury found the assault to be reckless."
Mr Nolan said: "The pre-sentence report makes it clear there's an element of almost revenge in the defendant's mind about this."
Mr Halligan's car was a write-off and he lost his job in Manchester because he needed to provide his own transport for the role.
The victim was taken to hospital by ambulance, where his eyes were washed out with saline solution, with one eye "irrigated".
Mr Nolan said: "Doctors were clear, very significant damage could have been caused to the cornea and he was fortunate that very significant damage was not caused."
Lloyd Morgan, defending, argued it was a "reckless" attack and while his client knew Mr Halligan was in the car, he was "aiming for the back seats".
He said the jury rejected the allegation Dennett intended to cause grievous bodily harm and suggested this "amounted to a rejection of the assertion by the prosecution that the defendant deliberately threw the liquid at Mr Halligan".
Mr Morgan said: "The prosecution case was the liquid was deliberately thrown at Mr Halligan. The defendant's case was it was not, it was actually thrown at the vehicle, but owing to either a poor aim or being reckless, it struck Mr Halligan.
He argued there wasn't a significant degree of planning and said Dennett wanted to damage the car, send out a "warning" and "scare" Mr Halligan, not harm him.
Mr Morgan said Dennett was a dad-of-two and if he was jailed, it would have a significant harmful impact on his children, who had suffered while he had been in custody for six and a half months.
Dennett had 22 previous convictions for 49 offences, including robbery, affray, thefts, criminal damage, public disorder and drugs matters, but Mr Morgan said the violent crimes were more than 20 years ago.
Recorder Harris accepted Dennett's plan had been to throw the fluid in the car to damage the interior and paintwork.
He said: "You knew, as you said in evidence, there was a possibility of the paint stripper going in his face."
However, the judge said he was sure when Dennett saw his victim, "you lost your temper and decided to throw the fluid at Mr Halligan".
Recorder Harris said: "The photos show the marks to his face. He said his face and eyes were burning and he required hospital treatment."
He said: "The driver's headrest was undamaged, demonstrating that the fluid was thrown towards the victim and not as you said, the back of the car."
Recorder Harris added: "I'm sure, having heard the evidence, that you threw that fluid at him."
He said there was a background to the attack, which he had ruled shouldn't be heard at the trial, but Dennett had still tried to introduce it "in my view to deflect the jury and to explain the need as you saw it to act as you did".
The judge added: "This merely reinforced your dislike of Mr Halligan and gave a reason for the attack.
"I do not make any findings on the background, but your attempts to break my rulings show your forceful nature and attitude to matters that you dislike."
Recorder Harris noted the pre-sentence report stated "you do not exhibit genuine remorse for your actions or demonstrate insight".
The judge said there was a significant degree of planning, adding: "The victim was vulnerable, he was unarmed.
"This was a mean, despicable and cowardly attack on him and you used a weapon.
"He wasn't to know that the corrosive fluid would not cause dreadful injuries to his eyesight and of course he did have damage to the cornea.
"Fortunately, mercifully, it was transient."
Recorder Harris made an indefinite restraining order to protect the victim.
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