Albion were incensed when Cazorla went down and earned his side a penalty when the sides met at the Emirates Stadium when TV replays showed there had been no contact with defender Steven Reid.
Striker Shane Long claimed afterwards that Cazorla's reaction to the award was that of "a guilty, guilty man".
But Clarke, who's side entertain Arsenal on Saturday, said: "What happened before is gone and we can't do anything about it. It's finished. I don't use revenge as motivation.
"It is just one of those contentious decisions that happens over a season. That was one of them.
"It gives you guys something to write about. That is the nature of football.
"Motivation should come from the fact we let ourselves down last week at West Ham and we want to put on a strong performance at home, which by and large we've done very well this season."
Clarke also challenged West Brom to end the season on a high note - to help them attract better quality signings to the club this summer.
The Baggies look set to secure back-to-back top-10 finishes in the Barclays Premier League, despite their form dipping in the new year.
Clarke admits the Baggies must continue to improve after guaranteeing a fourth successive year of top-flight football, although there is unlikely to be any gung-ho spending policy.
The Albion head coach said: "We have to improve again. This season is not finished. That is one thing I'm very conscious of.
"We've got 44 points, we are in eighth position. If we don't win another game, 44 points won't keep us there, we will fall down the league.
"We have to make sure we pick up more points this year and then in the summer we will decide what we need to take us from where we are this year to where we want to be next year.
"But the higher up the league we finish, the easier it will be to attract better quality players to the club.
"Every player wants to be part of a successful club or part of a club they think will challenge.
"Hopefully we can finish the season well and show everybody we're a club that can finish in the top half of the Premier League."
In terms of Albion's recruitment policy this summer, Clarke said: "We will do it carefully, as the club have always done.
"I don't see any reason why it should change because by and large the team has improved over the years. Over the last three years, the team has improved from year to year.
"What we have to try to do is improve next year. Whether that involved spending a little bit more money than we would normally do, is a discussion for people in the club.
"During the summer, you guys will see how much we spend because there is no hiding place from that."
Clarke added: "There are a lot of clubs in the past who have thrown money at a project to try and make a team better and it doesn't always work.
"You have to find the best way and that doesn't always mean spending £20 million and suddenly you are successful. It doesn't always happen like that.
"It can be if you're clever and you sign the right people for the right money, like Claudio Yacob for example. There are people there you can find for less money.
"But it might be as the summer goes on, if we can't find somebody who is going to cost us nothing, that we have to go and find someone who costs us money. That can be the case for sure."
Clarke has no doubt about the type of player and character he wants to sign.
He said: "Character-wise you want people who will fit into the dressing room, strong characters with good personalities.
"You want people who are determined and have a hunger to be successful."