diff --git a/src/color-handler.js b/src/color-handler.js
index 410bd3e..036f298 100644
--- a/src/color-handler.js
+++ b/src/color-handler.js
@@ -49,7 +49,7 @@
     }];
   }
 
-  scope.addPropertiesHandler(parseColor, mergeColors, ['color', 'backgroundColor']);
+  scope.addCssValueHandler(parseColor, mergeColors, 'rgb(1, 2, 3)');
 
   if (TESTING) {
     testing.parseColor = parseColor;
diff --git a/src/dimension-handler.js b/src/dimension-handler.js
index cea01dc..1e176e9 100644
--- a/src/dimension-handler.js
+++ b/src/dimension-handler.js
@@ -92,7 +92,6 @@
   scope.parseAngle = parseAngle;
   scope.mergeDimensions = mergeDimensions;
 
-  scope.addPropertiesHandler(parseLengthOrPercent, mergeDimensions,
-      'left|right|top|bottom|width|height'.split('|'));
+  scope.addCssValueHandler(parseLengthOrPercent, mergeDimensions, '12em');
 
 })(minifill, testing);
diff --git a/src/number-handler.js b/src/number-handler.js
index 32431c8..da39913 100644
--- a/src/number-handler.js
+++ b/src/number-handler.js
@@ -39,7 +39,7 @@
     };
   }
 
-  scope.addPropertiesHandler(parseNumber, clampedMergeNumbers(0, 1), ['opacity']);
+  scope.addCssValueHandler(parseNumber, clampedMergeNumbers(0, 1), '0.5');
 
   scope.parseNumber = parseNumber;
   scope.mergeNumbers = mergeNumbers;
diff --git a/src/property-interpolation.js b/src/property-interpolation.js
index d07f913..49b8797 100644
--- a/src/property-interpolation.js
+++ b/src/property-interpolation.js
@@ -16,14 +16,34 @@
 
   var propertyHandlers = {};
 
-  function addPropertiesHandler(parser, merger, properties) {
-    for (var i = 0; i < properties.length; i++) {
-      var property = properties[i];
-      propertyHandlers[property] = propertyHandlers[property] || [];
-      propertyHandlers[property].push([parser, merger]);
+  function propertiesAcceptingCssValue(cssValue) {
+    var properties = [];
+    var style = document.createElement('div').style;
+    for (var property in style) {
+      if (style[property] !== '')
+        continue;
+      var rejected = ['webkit', 'Moz', 'ms', 'animation', 'transition'].some(function(disallowed) {
+        return property.indexOf(disallowed) === 0;
+      });
+      if (rejected)
+        continue;
+      // style['content'] = 'css value' throws in IE.
+      try {
+        style[property] = cssValue;
+        if (style[property] === cssValue)
+          properties.push(property);
+      } catch (error) {}
+      style[property] = '';
     }
+    return properties;
   }
-  scope.addPropertiesHandler = addPropertiesHandler;
+
+  scope.addCssValueHandler = function(parser, merger, cssValue) {
+    propertiesAcceptingCssValue(cssValue).forEach(function(property) {
+      propertyHandlers[property] = propertyHandlers[property] || [];
+      propertyHandlers[property].push([parser, merger]);
+    });
+  };
 
   function propertyInterpolation(property, left, right) {
     var handlers = left == right ? [] : propertyHandlers[property];
diff --git a/src/transform-handler.js b/src/transform-handler.js
index 1efbdc5..af7afaa 100644
--- a/src/transform-handler.js
+++ b/src/transform-handler.js
@@ -192,7 +192,7 @@
     }];
   }
 
-  scope.addPropertiesHandler(parseTransform, mergeTransforms, ['transform']);
+  scope.addCssValueHandler(parseTransform, mergeTransforms, 'rotate(10deg) scale(2)');
 
   if (TESTING) {
     testing.parseTransform = parseTransform;