diff --git a/ii.c b/ii.c
index 72e59b5..6583792 100644
--- a/ii.c
+++ b/ii.c
@@ -141,7 +141,7 @@ channel_normalize_path(char *s)
 	for (; *s; s++) {
 		if (isalpha(*s))
 			*s = tolower(*s);
-		else if (!isdigit(*s) && !strchr(".#&", *s))
+		else if (!isdigit(*s) && !strchr(".#&+!-", *s))
 			*s = '_';
 	}
 }