diff --git a/include/aoc/framework/Solver-impl.hpp b/include/aoc/framework/Solver-impl.hpp
index 07fd066..b7de834 100644
--- a/include/aoc/framework/Solver-impl.hpp
+++ b/include/aoc/framework/Solver-impl.hpp
@@ -17,6 +17,7 @@
 
 #include <aoc/framework/Solver.hpp>
 
+#include <algorithm>
 #include <sstream>
 
 template <typename T1, typename T2>
@@ -54,10 +55,7 @@ template <typename T1, typename T2>
 std::string Solver<T1, T2>::clean(const std::string& original) const
 {
     std::string cleaned{ original };
-    size_t start_pos = 0;
-    while ((start_pos = cleaned.find(" ", start_pos)) != std::string::npos)
-    {
-        cleaned.replace(start_pos, 1, "_");
-    }
+    std::transform(cleaned.begin(), cleaned.end(), cleaned.begin(),
+        [](unsigned char c) { return c == ' ' ? '_' : std::tolower(c); });
     return cleaned;
 }