diff --git a/lib/libmixer/mixer.c b/lib/libmixer/mixer.c
--- a/lib/libmixer/mixer.c
+++ b/lib/libmixer/mixer.c
@@ -39,9 +39,6 @@
 
 static int _mixer_readvol(struct mixer *, struct mix_dev *);
 
-/*
- * Fetch volume from the device.
- */
 static int
 _mixer_readvol(struct mixer *m, struct mix_dev *dev)
 {
@@ -79,7 +76,6 @@
 		if (strncmp(name, BASEPATH, strlen(BASEPATH)) != 0) {
 			m->unit = -1;
 		} else {
-			/* `name` is "/dev/mixer" so, we'll use the default unit. */
 			if (strncmp(name, BASEPATH, strlen(name)) == 0)
 				goto dunit;
 			m->unit = strtol(name + strlen(BASEPATH), NULL, 10);
@@ -141,9 +137,6 @@
 	return (NULL);
 }
 
-/*
- * Free resources and close the mixer.
- */
 int
 mixer_close(struct mixer *m)
 {
@@ -208,9 +201,6 @@
 	return (NULL);
 }
 
-/*
- * Add a mixer control to a device.
- */
 int
 mixer_add_ctl(struct mix_dev *parent_dev, int id, const char *name,
     int (*mod)(struct mix_dev *, void *),
@@ -233,7 +223,6 @@
 	ctl->mod = mod;
 	ctl->print = print;
 	dp = ctl->parent_dev;
-	/* Make sure the same ID or name doesn't exist already. */
 	TAILQ_FOREACH(cp, &dp->ctls, ctls) {
 		if (!strncmp(cp->name, name, sizeof(cp->name)) || cp->id == id) {
 			errno = EINVAL;
@@ -246,9 +235,6 @@
 	return (0);
 }
 
-/*
- * Same as `mixer_add_ctl`.
- */
 int
 mixer_add_ctl_s(mix_ctl_t *ctl)
 {
@@ -259,9 +245,6 @@
 	    ctl->mod, ctl->print));
 }
 
-/*
- * Remove a mixer control from a device.
- */
 int
 mixer_remove_ctl(mix_ctl_t *ctl)
 {
@@ -280,9 +263,6 @@
 	return (0);
 }
 
-/*
- * Get a mixer control by id.
- */
 mix_ctl_t *
 mixer_get_ctl(struct mix_dev *d, int id)
 {
@@ -297,9 +277,6 @@
 	return (NULL);
 }
 
-/*
- * Get a mixer control by name.
- */
 mix_ctl_t *
 mixer_get_ctl_byname(struct mix_dev *d, const char *name)
 {
@@ -415,10 +392,6 @@
 	return (0);
 }
 
-/*
- * Get default audio card's number. This is used to open the default mixer
- * and set the mixer structure's `f_default` flag.
- */
 int
 mixer_get_dunit(void)
 {
@@ -453,10 +426,6 @@
 	return (0);
 }
 
-/*
- * Get sound device mode (none, play, rec, play+rec). Userland programs can
- * use the MIX_MODE_* flags to determine the mode of the device.
- */
 int
 mixer_get_mode(int unit)
 {
@@ -472,19 +441,13 @@
 	return (mode);
 }
 
-/*
- * Get the total number of mixers in the system.
- */
 int
 mixer_get_nmixers(void)
 {
 	struct mixer *m;
 	oss_sysinfo si;
 
-	/*
-	 * Open a dummy mixer because we need the `fd` field for the
-	 * `ioctl` to work.
-	 */
+	/* Dummy device. */
 	if ((m = mixer_open(NULL)) == NULL)
 		return (-1);
 	if (ioctl(m->fd, OSS_SYSINFO, &si) < 0) {