diff --git a/src/ColDefFactory.jsx b/src/ColDefFactory.jsx
index 41d049a..3bd22a3 100644
--- a/src/ColDefFactory.jsx
+++ b/src/ColDefFactory.jsx
@@ -22,6 +22,7 @@ export default class ColDefFactory {
                     {headerName: "Name", field: "name",
                         width: 150, pinned: true},
                     {headerName: "Country", field: "country", width: 150,
+                        // not bothering with React for country, as it's a simple HTML string
                         cellRenderer: countryCellRenderer, pinned: true,
                         filterParams: {cellRenderer: countryCellRenderer, cellHeight: 20}},
                 ]
@@ -30,11 +31,15 @@ export default class ColDefFactory {
                 headerName: 'IT Skills',
                 children: [
                     {headerName: "Skills", width: 125, suppressSorting: true, field: 'skills',
+                        // using ag-Grid's React cellRenderer factory
                         cellRenderer: reactCellRendererFactory(SkillsCellRenderer),
+                        // using ag-Grid's React filter factory
                         filter: reactFilterFactory(SkillsFilter)
                     },
                     {headerName: "Proficiency", field: "proficiency", filter: 'number', width: 120,
+                        // using ag-Grid's React cellRenderer factory
                         cellRenderer: reactCellRendererFactory(ProficiencyCellRenderer),
+                        // using ag-Grid's React filter factory
                         filter: reactFilterFactory(ProficiencyFilter)}
                 ]
             },
@@ -54,155 +59,8 @@ export default class ColDefFactory {
 // this is a simple cell renderer, putting together static html, no
 // need to use React for it.
 function countryCellRenderer(params) {
-    var flag = "<img border='0' width='15' height='10' style='margin-bottom: 2px' src='http://flags.fmcdn.net/data/flags/mini/" + RefData.COUNTRY_CODES[params.value] + ".png'>";
+    var flag = "<img border='0' width='15' height='10' " +
+        "style='margin-bottom: 2px' src='http://flags.fmcdn.net/data/flags/mini/"
+        + RefData.COUNTRY_CODES[params.value] + ".png'>";
     return flag + " " + params.value;
 }
-/*
-var SKILL_TEMPLATE =
-    '<label style="border: 1px solid lightgrey; margin: 4px; padding: 4px; display: inline-block;">' +
-    '  <span>' +
-    '    <div style="text-align: center;">SKILL_NAME</div>' +
-    '    <div>' +
-    '      <input type="checkbox"/>' +
-    '      <img src="images/skills/SKILL.png" width="30px"/>' +
-    '    </div>' +
-    '  </span>' +
-    '</label>';
-
-var FILTER_TITLE =
-    '<div style="text-align: center; background: lightgray; width: 100%; display: block; border-bottom: 1px solid grey;">' +
-    '<b>TITLE_NAME</b>' +
-    '</div>';*/
-/*
-function SkillFilter() {
-}
-
-SkillFilter.prototype.init = function (params) {
-    this.filterChangedCallback = params.filterChangedCallback;
-    this.model = {
-        android: false,
-        css: false,
-        html5: false,
-        mac: false,
-        windows: false
-    };
-};
-
-SkillFilter.prototype.getGui = function () {
-    var eGui = document.createElement('div');
-    eGui.style.width = '380px';
-    var eInstructions = document.createElement('div');
-    eInstructions.innerHTML = FILTER_TITLE.replace('TITLE_NAME', 'Custom Skills Filter');
-    eGui.appendChild(eInstructions);
-
-    var that = this;
-
-    RefData.IT_SKILLS.forEach(function (skill, index) {
-        var skillName = RefData.IT_SKILLS_NAMES[index];
-        var eSpan = document.createElement('span');
-        var html = SKILL_TEMPLATE.replace("SKILL_NAME", skillName).replace("SKILL", skill);
-        eSpan.innerHTML = html;
-
-        var eCheckbox = eSpan.querySelector('input');
-        eCheckbox.addEventListener('click', function () {
-            that.model[skill] = eCheckbox.checked;
-            that.filterChangedCallback();
-        });
-
-        eGui.appendChild(eSpan);
-    });
-
-    return eGui;
-};
-
-SkillFilter.prototype.doesFilterPass = function (params) {
-
-    var rowSkills = params.data.skills;
-    var model = this.model;
-    var passed = true;
-
-    IT_SKILLS.forEach(function (skill) {
-        if (model[skill]) {
-            if (!rowSkills[skill]) {
-                passed = false;
-            }
-        }
-    });
-
-    return passed;
-};
-
-SkillFilter.prototype.isFilterActive = function () {
-    var model = this.model;
-    var somethingSelected = model.android || model.css || model.html5 || model.mac || model.windows;
-    return somethingSelected;
-};*/
-//
-//var PROFICIENCY_TEMPLATE =
-//    '<label style="padding-left: 4px;">' +
-//    '<input type="radio" name="RANDOM"/>' +
-//    'PROFICIENCY_NAME' +
-//    '</label>';
-//
-//var PROFICIENCY_NONE = 'none';
-//var PROFICIENCY_ABOVE40 = 'above40';
-//var PROFICIENCY_ABOVE60 = 'above60';
-//var PROFICIENCY_ABOVE80 = 'above80';
-//
-//var PROFICIENCY_NAMES = ['No Filter', 'Above 40%', 'Above 60%', 'Above 80%'];
-//var PROFICIENCY_VALUES = [PROFICIENCY_NONE, PROFICIENCY_ABOVE40, PROFICIENCY_ABOVE60, PROFICIENCY_ABOVE80];
-//
-//function ProficiencyFilter() {
-//}
-//
-//ProficiencyFilter.prototype.init = function (params) {
-//    this.filterChangedCallback = params.filterChangedCallback;
-//    this.selected = PROFICIENCY_NONE;
-//    this.valueGetter = params.valueGetter;
-//};
-//
-//ProficiencyFilter.prototype.getGui = function () {
-//    var eGui = document.createElement('div');
-//    var eInstructions = document.createElement('div');
-//    eInstructions.innerHTML = FILTER_TITLE.replace('TITLE_NAME', 'Custom Proficiency Filter');
-//    eGui.appendChild(eInstructions);
-//
-//    var random = '' + Math.random();
-//
-//    var that = this;
-//    PROFICIENCY_NAMES.forEach( function (name, index) {
-//        var eFilter = document.createElement('div');
-//        var html = PROFICIENCY_TEMPLATE.replace('PROFICIENCY_NAME', name).replace('RANDOM', random);
-//        eFilter.innerHTML = html;
-//        var eRadio = eFilter.querySelector('input');
-//        if (index === 0) {
-//            eRadio.checked = true;
-//        }
-//        eGui.appendChild(eFilter);
-//
-//        eRadio.addEventListener('click', function () {
-//            that.selected = PROFICIENCY_VALUES[index];
-//            that.filterChangedCallback();
-//        });
-//    });
-//
-//    return eGui;
-//};
-//
-//ProficiencyFilter.prototype.doesFilterPass = function (params) {
-//
-//    var value = this.valueGetter(params);
-//    var valueAsNumber = parseFloat(value);
-//
-//    switch (this.selected) {
-//        case PROFICIENCY_ABOVE40 : return valueAsNumber >= 40;
-//        case PROFICIENCY_ABOVE60 : return valueAsNumber >= 60;
-//        case PROFICIENCY_ABOVE80 : return valueAsNumber >= 80;
-//        default : return true;
-//    }
-//
-//};
-//
-//ProficiencyFilter.prototype.isFilterActive = function () {
-//    return this.selected !== PROFICIENCY_NONE;
-//};