diff --git a/src/solvers/cafeteria.rs b/src/solvers/cafeteria.rs
index 89b919f..02b1116 100644
--- a/src/solvers/cafeteria.rs
+++ b/src/solvers/cafeteria.rs
@@ -5,6 +5,10 @@ use std::io::BufRead;
 
 pub struct Cafeteria {}
 
+impl Cafeteria {
+    const INTERVAL_SPLIT_CHAR: char = '-';
+}
+
 impl Solver for Cafeteria {
     const PUZZLE_INDEX: u8 = 5;
     const PUZZLE_NAME: &'static str = "Cafeteria";
@@ -17,7 +21,8 @@ impl Solver for Cafeteria {
             .lines()
             .map_while(|x| x.ok().filter(|s| !s.is_empty()))
         {
-            let values: Vec<u64> = line.split('-').map_while(|s| s.parse().ok()).collect();
+            // TODO: This code should move into new common::interval::MultiInterval struct.
+            let values: Vec<u64> = line.split(Self::INTERVAL_SPLIT_CHAR).map_while(|s| s.parse().ok()).collect();
             let mut interval = Interval::new(values[0], values[1]);
 
             let mut to_delete = Vec::new();
diff --git a/src/solvers/playground.rs b/src/solvers/playground.rs
index a244b75..e2cc7fd 100644
--- a/src/solvers/playground.rs
+++ b/src/solvers/playground.rs
@@ -8,6 +8,7 @@ pub struct Playground {
 }
 
 impl Playground {
+    const POINT_SPLIT_CHAR: char = ',';
     const CIRCUITS_TAKE: usize = 3;
 
     pub fn new(connections: Option<usize>) -> Playground {
@@ -20,7 +21,7 @@ impl Playground {
     fn junction_boxes<R: BufRead>(reader: R) -> Vec<Point3> {
         let mut junction_boxes = Vec::new();
         for line in reader.lines().map_while(Result::ok) {
-            let j: Vec<u64> = line.split(',').map(|s| s.parse().unwrap()).collect();
+            let j: Vec<u64> = line.split(Self::POINT_SPLIT_CHAR).map(|s| s.parse().unwrap()).collect();
             junction_boxes.push(Point3(j[0], j[1], j[2]));
         }
         junction_boxes
diff --git a/src/solvers/printing_department.rs b/src/solvers/printing_department.rs
index 1c865b8..9d4c541 100644
--- a/src/solvers/printing_department.rs
+++ b/src/solvers/printing_department.rs
@@ -4,6 +4,10 @@ use std::io::BufRead;
 
 pub struct PrintingDepartment {}
 
+impl PrintingDepartment {
+    const PAPER_ROLL_CHAR: char = '@';
+}
+
 impl Solver for PrintingDepartment {
     const PUZZLE_INDEX: u8 = 4;
     const PUZZLE_NAME: &'static str = "Printing Department";
@@ -11,7 +15,7 @@ impl Solver for PrintingDepartment {
     fn process_data<R: BufRead>(&self, reader: R) -> (u64, u64) {
         let mut grid = Grid::new(0, 0);
         for line in reader.lines().map_while(Result::ok) {
-            grid.push_row(line.bytes().map(|c| c == b'@').collect());
+            grid.push_row(line.bytes().map(|c| c == Self::PAPER_ROLL_CHAR as u8).collect());
         }
 
         let mut part1 = 0;
diff --git a/src/solvers/trash_compactor.rs b/src/solvers/trash_compactor.rs
index f4eca2a..566d129 100644
--- a/src/solvers/trash_compactor.rs
+++ b/src/solvers/trash_compactor.rs
@@ -4,6 +4,10 @@ use std::io::BufRead;
 
 pub struct TrashCompactor {}
 
+impl TrashCompactor {
+    const NUMBER_SPLIT_CHAR: char = ' ';
+}
+
 impl Solver for TrashCompactor {
     const PUZZLE_INDEX: u8 = 6;
     const PUZZLE_NAME: &'static str = "Trash Compactor";
@@ -12,7 +16,7 @@ impl Solver for TrashCompactor {
         let mut part1 = 0;
         let mut grid = Grid::new(0, 0);
         for line in reader.lines().map_while(Result::ok) {
-            let v: Vec<&str> = line.split(' ').filter(|s| !s.is_empty()).collect();
+            let v: Vec<&str> = line.split(Self::NUMBER_SPLIT_CHAR).filter(|s| !s.is_empty()).collect();
             match v[0].parse::<u32>() {
                 Ok(_) => grid.push_row(v.iter().map(|n| n.parse::<u64>().unwrap()).collect()),
                 Err(_) => {