diff --git a/prism/src/prism/StateModelChecker.java b/prism/src/prism/StateModelChecker.java
index 328a94de..5930d6a5 100644
--- a/prism/src/prism/StateModelChecker.java
+++ b/prism/src/prism/StateModelChecker.java
@@ -146,7 +146,7 @@ public class StateModelChecker implements ModelChecker
 
 		// Create storage for result
 		result = new Result();
-		
+
 		// The final result of model checking will be a single value. If the expression to be checked does not
 		// already yield a single value (e.g. because a filter has not been explicitly included), we need to wrap
 		// a new (invisible) filter around it. Note that some filters (e.g. print/argmin/argmax) also do not
@@ -179,7 +179,7 @@ public class StateModelChecker implements ModelChecker
 			// We stop any additional explanation being displayed to avoid confusion.
 			exprFilter.setExplanationEnabled(false);
 		}
-		
+
 		// For any case where a new filter was created above...
 		if (exprFilter != null) {
 			// Make it invisible (not that it will be displayed)
@@ -202,7 +202,7 @@ public class StateModelChecker implements ModelChecker
 			resultString += " (" + expr.getResultName().toLowerCase() + ")";
 		resultString += ": " + result.getResultString();
 		mainLog.print("\n" + resultString + "\n");
-		
+
 		// Clean up
 		vals.clear();
 
@@ -340,8 +340,6 @@ public class StateModelChecker implements ModelChecker
 				res1.clear();
 			if (res2 != null)
 				res2.clear();
-			if (res3 != null)
-				res3.clear();
 			throw e;
 		}
 
@@ -391,8 +389,6 @@ public class StateModelChecker implements ModelChecker
 		} catch (PrismException e) {
 			if (res1 != null)
 				res1.clear();
-			if (res2 != null)
-				res2.clear();
 			throw e;
 		}
 
@@ -591,8 +587,6 @@ public class StateModelChecker implements ModelChecker
 		} catch (PrismException e) {
 			if (res1 != null)
 				res1.clear();
-			if (res2 != null)
-				res2.clear();
 			throw e;
 		}
 		dd1 = res1.convertToStateValuesMTBDD().getJDDNode();
@@ -632,13 +626,7 @@ public class StateModelChecker implements ModelChecker
 		int i, n, op = expr.getOperator();
 
 		// Check operand recursively
-		try {
-			res1 = checkExpression(expr.getOperand());
-		} catch (PrismException e) {
-			if (res1 != null)
-				res1.clear();
-			throw e;
-		}
+		res1 = checkExpression(expr.getOperand());
 
 		// Parentheses are easy - nothing to do:
 		if (op == ExpressionUnaryOp.PARENTH)
@@ -708,13 +696,7 @@ public class StateModelChecker implements ModelChecker
 		int i, n, op = expr.getNameCode();
 
 		// Check operand recursively
-		try {
-			res1 = checkExpression(expr.getOperand(0));
-		} catch (PrismException e) {
-			if (res1 != null)
-				res1.clear();
-			throw e;
-		}
+		res1 = checkExpression(expr.getOperand(0));
 		// Symbolic
 		if (res1 instanceof StateValuesMTBDD) {
 			dd1 = ((StateValuesMTBDD) res1).getJDDNode();
@@ -765,8 +747,6 @@ public class StateModelChecker implements ModelChecker
 		} catch (PrismException e) {
 			if (res1 != null)
 				res1.clear();
-			if (res2 != null)
-				res2.clear();
 			throw e;
 		}
 		// If both operands are symbolic, result will be symbolic
@@ -851,13 +831,7 @@ public class StateModelChecker implements ModelChecker
 		boolean symbolic;
 
 		// Check first operand recursively
-		try {
-			res1 = checkExpression(expr.getOperand(0));
-		} catch (PrismException e) {
-			if (res1 != null)
-				res1.clear();
-			throw e;
-		}
+		res1 = checkExpression(expr.getOperand(0));
 		// Go through remaining operands
 		// Switch to explicit as soon as an operand is explicit
 		n = expr.getNumOperands();