diff --git a/collector/devstat_dragonfly.go b/collector/devstat_dragonfly.go
index 13aa1a55..95639917 100644
--- a/collector/devstat_dragonfly.go
+++ b/collector/devstat_dragonfly.go
@@ -124,7 +124,7 @@ func NewDevstatCollector() (Collector, error) {
 	}, nil
 }
 
-func (c *devstatCollector) Update(ch chan<- prometheus.Metric) (err error) {
+func (c *devstatCollector) Update(ch chan<- prometheus.Metric) error {
 	count := C._get_ndevs()
 	if count == -1 {
 		return errors.New("getdevs() failed")
diff --git a/collector/exec_bsd.go b/collector/exec_bsd.go
index 0c794583..07beb518 100644
--- a/collector/exec_bsd.go
+++ b/collector/exec_bsd.go
@@ -28,7 +28,7 @@ func init() {
 	Factories["exec"] = NewExecCollector
 }
 
-// NewExecCollector returns a new Collector exposing system execution statistics
+// NewExecCollector returns a new Collector exposing system execution statistics.
 func NewExecCollector() (Collector, error) {
 	// From sys/vm/vm_meter.c:
 	// All are of type CTLTYPE_UINT.
@@ -77,15 +77,13 @@ func NewExecCollector() (Collector, error) {
 }
 
 // Update pushes exec statistics onto ch
-func (c *execCollector) Update(ch chan<- prometheus.Metric) (err error) {
+func (c *execCollector) Update(ch chan<- prometheus.Metric) error {
 	for _, m := range c.sysctls {
 		v, err := m.Value()
 		if err != nil {
 			return err
 		}
 
-		// We "know" all of our sysctls are CounterValues, let's skip
-		// parsing them
 		ch <- prometheus.MustNewConstMetric(
 			prometheus.NewDesc(
 				prometheus.BuildFQName(Namespace, "exec", m.name),
diff --git a/collector/hwmon_linux.go b/collector/hwmon_linux.go
index c1f4ea4c..da05204e 100644
--- a/collector/hwmon_linux.go
+++ b/collector/hwmon_linux.go
@@ -101,7 +101,7 @@ func explodeSensorFilename(filename string) (ok bool, sensorType string, sensorN
 	return true, sensorType, sensorNum, sensorProperty
 }
 
-func collectSensorData(dir string, data map[string]map[string]string) (err error) {
+func collectSensorData(dir string, data map[string]map[string]string) error {
 	sensorFiles, dirError := ioutil.ReadDir(dir)
 	if dirError != nil {
 		return dirError
@@ -123,7 +123,7 @@ func collectSensorData(dir string, data map[string]map[string]string) (err error
 	return nil
 }
 
-func (c *hwMonCollector) updateHwmon(ch chan<- prometheus.Metric, dir string) (err error) {
+func (c *hwMonCollector) updateHwmon(ch chan<- prometheus.Metric, dir string) error {
 	hwmonName, err := c.hwmonName(dir)
 	if err != nil {
 		return err
diff --git a/collector/zfs_linux.go b/collector/zfs_linux.go
index f6515bad..6774efa9 100644
--- a/collector/zfs_linux.go
+++ b/collector/zfs_linux.go
@@ -47,7 +47,7 @@ func (c *zfsCollector) updateZfsStats(subsystem string, ch chan<- prometheus.Met
 	})
 }
 
-func (c *zfsCollector) updatePoolStats(ch chan<- prometheus.Metric) (err error) {
+func (c *zfsCollector) updatePoolStats(ch chan<- prometheus.Metric) error {
 	zpoolPaths, err := filepath.Glob(procFilePath(filepath.Join(c.linuxProcpathBase, c.linuxZpoolIoPath)))
 	if err != nil {
 		return err