diff --git a/comparexlsxlsx.go b/comparexlsxlsx.go
deleted file mode 100644
index a161abd..0000000
--- a/comparexlsxlsx.go
+++ /dev/null
@@ -1,55 +0,0 @@
-package xls
-
-import (
-	"fmt"
-	"github.com/tealeg/xlsx"
-	"math"
-	"strconv"
-)
-
-//Compares xls and xlsx files
-func CompareXlsXlsx(xlsfilepathname string, xlsxfilepathname string) string {
-	xlsFile, err := Open(xlsfilepathname, "utf-8")
-	if err != nil {
-		return fmt.Sprintf("Cant open xls file: %s", err)
-	}
-
-	xlsxFile, err := xlsx.OpenFile(xlsxfilepathname)
-	if err != nil {
-		return fmt.Sprintf("Cant open xlsx file: %s", err)
-	}
-
-	for sheet, xlsxSheet := range xlsxFile.Sheets {
-		xlsSheet := xlsFile.GetSheet(sheet)
-		if xlsSheet == nil {
-			return fmt.Sprintf("Cant get xls sheet")
-		}
-		for row, xlsxRow := range xlsxSheet.Rows {
-			xlsRow := xlsSheet.Row(row)
-			for cell, xlsxCell := range xlsxRow.Cells {
-				xlsxText := xlsxCell.String()
-				xlsText := xlsRow.Col(cell)
-				if xlsText != xlsxText {
-					//try to convert to numbers
-					xlsFloat, xlsErr := strconv.ParseFloat(xlsText, 64)
-					xlsxFloat, xlsxErr := strconv.ParseFloat(xlsxText, 64)
-					//check if numbers have no significant difference
-					if xlsErr == nil && xlsxErr == nil {
-						diff := math.Abs(xlsFloat - xlsxFloat)
-						if diff > 0.0000001 {
-							return fmt.Sprintf("sheet:%d, row/col: %d/%d, xlsx: (%s)[%d], xls: (%s)[%d], numbers difference: %f.",
-								sheet, row, cell, xlsxText, len(xlsxText),
-								xlsText, len(xlsText), diff)
-						}
-					} else {
-						return fmt.Sprintf("sheet:%d, row/col: %d/%d, xlsx: (%s)[%d], xls: (%s)[%d].",
-							sheet, row, cell, xlsxText, len(xlsxText),
-							xlsText, len(xlsText))
-					}
-				}
-			}
-		}
-	}
-
-	return ""
-}
diff --git a/issue47_test.go b/issue47_test.go
deleted file mode 100644
index 1385ad3..0000000
--- a/issue47_test.go
+++ /dev/null
@@ -1,30 +0,0 @@
-package xls
-
-import (
-	"io/ioutil"
-	"path"
-	"path/filepath"
-	"strings"
-	"testing"
-)
-
-func TestIssue47(t *testing.T) {
-	testdatapath := "testdata"
-	files, err := ioutil.ReadDir(testdatapath)
-	if err != nil {
-		t.Fatalf("Cant read testdata directory contents: %s", err)
-	}
-	for _, f := range files {
-		if filepath.Ext(f.Name()) == ".xls" {
-			xlsfilename := f.Name()
-			xlsxfilename := strings.TrimSuffix(xlsfilename, filepath.Ext(xlsfilename)) + ".xlsx"
-			err := CompareXlsXlsx(path.Join(testdatapath, xlsfilename),
-				path.Join(testdatapath, xlsxfilename))
-			if err != "" {
-				t.Fatalf("XLS file %s an XLSX file are not equal: %s", xlsfilename, err)
-			}
-
-		}
-	}
-
-}
diff --git a/testdata/bigtable.xls b/testdata/bigtable.xls
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index e7c7481..0000000
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diff --git a/testdata/bigtable.xlsx b/testdata/bigtable.xlsx
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index b54c6fb..0000000
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diff --git a/testdata/float.xls b/testdata/float.xls
deleted file mode 100644
index dbe9585..0000000
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diff --git a/testdata/float.xlsx b/testdata/float.xlsx
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index f399236..0000000
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diff --git a/testdata/issue47.xls b/testdata/issue47.xls
deleted file mode 100644
index 866f246..0000000
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diff --git a/testdata/issue47.xlsx b/testdata/issue47.xlsx
deleted file mode 100644
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diff --git a/testdata/negatives.xls b/testdata/negatives.xls
deleted file mode 100644
index 47902e3..0000000
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diff --git a/testdata/negatives.xlsx b/testdata/negatives.xlsx
deleted file mode 100644
index 0d705cc..0000000
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diff --git a/testdata/superstore.xls b/testdata/superstore.xls
deleted file mode 100644
index 34c7090..0000000
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diff --git a/testdata/superstore.xlsx b/testdata/superstore.xlsx
deleted file mode 100644
index b610f26..0000000
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diff --git a/testdata/times.xls b/testdata/times.xls
deleted file mode 100644
index 585797e..0000000
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diff --git a/testdata/times.xlsx b/testdata/times.xlsx
deleted file mode 100644
index 8020038..0000000
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