diff --git a/splitter/nicehash/gc_test.go b/splitter/nicehash/gc_test.go
new file mode 100644
index 0000000..2f22458
--- /dev/null
+++ b/splitter/nicehash/gc_test.go
@@ -0,0 +1,92 @@
+package nicehash
+
+import (
+	"sync"
+	"testing"
+	"time"
+)
+
+type gcStrategy struct {
+	mu           sync.Mutex
+	disconnected bool
+	active       bool
+}
+
+func (s *gcStrategy) Connect() {}
+
+func (s *gcStrategy) Submit(jobID, nonce, result, algo string) int64 {
+	return 0
+}
+
+func (s *gcStrategy) Disconnect() {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.disconnected = true
+}
+
+func (s *gcStrategy) IsActive() bool {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.active
+}
+
+func TestNonceSplitter_GC_Good(t *testing.T) {
+	strategy := &gcStrategy{active: false}
+	mapper := &NonceMapper{
+		id:       42,
+		storage:  NewNonceStorage(),
+		strategy: strategy,
+		lastUsed: time.Now().Add(-2 * time.Minute),
+		pending:  make(map[int64]SubmitContext),
+	}
+	mapper.storage.slots[0] = -1
+
+	splitter := &NonceSplitter{
+		mappers: []*NonceMapper{mapper},
+		byID:    map[int64]*NonceMapper{mapper.id: mapper},
+	}
+
+	splitter.GC()
+
+	if len(splitter.mappers) != 0 {
+		t.Fatalf("expected idle mapper to be reclaimed, got %d mapper(s)", len(splitter.mappers))
+	}
+	if _, ok := splitter.byID[mapper.id]; ok {
+		t.Fatalf("expected reclaimed mapper to be removed from lookup table")
+	}
+	if !strategy.disconnected {
+		t.Fatalf("expected reclaimed mapper strategy to be disconnected")
+	}
+}
+
+func TestNonceSplitter_GC_Bad(t *testing.T) {
+	var splitter *NonceSplitter
+
+	splitter.GC()
+}
+
+func TestNonceSplitter_GC_Ugly(t *testing.T) {
+	strategy := &gcStrategy{active: true}
+	mapper := &NonceMapper{
+		id:       99,
+		storage:  NewNonceStorage(),
+		strategy: strategy,
+		lastUsed: time.Now().Add(-2 * time.Minute),
+		pending:  make(map[int64]SubmitContext),
+	}
+	mapper.storage.slots[0] = 7
+
+	splitter := &NonceSplitter{
+		mappers: []*NonceMapper{mapper},
+		byID:    map[int64]*NonceMapper{mapper.id: mapper},
+	}
+
+	splitter.GC()
+
+	if len(splitter.mappers) != 1 {
+		t.Fatalf("expected active mapper to remain, got %d mapper(s)", len(splitter.mappers))
+	}
+	if strategy.disconnected {
+		t.Fatalf("expected active mapper to stay connected")
+	}
+}
diff --git a/splitter/nicehash/impl.go b/splitter/nicehash/impl.go
index eb8d8aa..4e999c3 100644
--- a/splitter/nicehash/impl.go
+++ b/splitter/nicehash/impl.go
@@ -98,13 +98,17 @@ func (s *NonceSplitter) GC() {
 	now := time.Now()
 	next := s.mappers[:0]
 	for _, mapper := range s.mappers {
+		if mapper == nil || mapper.storage == nil {
+			continue
+		}
 		free, dead, active := mapper.storage.SlotCount()
-		if active == 0 && dead == 0 && now.Sub(mapper.lastUsed) > time.Minute {
+		if active == 0 && now.Sub(mapper.lastUsed) > time.Minute {
 			if mapper.strategy != nil {
 				mapper.strategy.Disconnect()
 			}
 			delete(s.byID, mapper.id)
 			_ = free
+			_ = dead
 			continue
 		}
 		next = append(next, mapper)