diff --git a/android/Android.mk b/android/Android.mk
index 2168dde..492d295 100644
--- a/android/Android.mk
+++ b/android/Android.mk
@@ -15,6 +15,24 @@
 
 LOCAL_PATH := $(abspath $(call my-dir)/..)
 
+# Force a clean if target API has changed and a previous build exists
+ifneq ("$(wildcard $(LOCAL_PATH)/libs/$(TARGET_ARCH_ABI)/android_api.txt)","")
+  CACHED_API := $(shell cat "$(LOCAL_PATH)/libs/$(TARGET_ARCH_ABI)/android_api.txt")
+  ifneq ($(ANDROID_API),$(CACHED_API))
+    $(info [!] Previous build was targeting different API level - cleaning)
+    DUMMY_CLEAN := $(shell make clean)
+  endif
+endif
+
+# Force a clean if selected toolchain has changed and a previous build exists
+ifneq ("$(wildcard $(LOCAL_PATH)/libs/$(TARGET_ARCH_ABI)/ndk_toolchain.txt)","")
+  CACHED_TOOLCHAIN := $(shell cat "$(LOCAL_PATH)/libs/$(TARGET_ARCH_ABI)/ndk_toolchain.txt")
+  ifneq ($(NDK_TOOLCHAIN),$(CACHED_TOOLCHAIN))
+    $(info [!] Previous build was using different toolchain - cleaning)
+    DUMMY_CLEAN := $(shell make clean)
+  endif
+endif
+
 # Enable Linux ptrace() instead of POSIX signal interface by default
 ANDROID_WITH_PTRACE ?= true
 
@@ -161,9 +179,13 @@
 include $(BUILD_EXECUTABLE)
 
 # The NDK build system does not copy static libraries into project/packages
-# so it has to be done manually in order to have all output under a single path
+# so it has to be done manually in order to have all output under a single path.
+# Also save some build attribute cache files so that cleans can be enforced when
+# required.
 all:POST_BUILD_EVENT
 POST_BUILD_EVENT:
+	@echo $(ANDROID_API) > $(LOCAL_PATH)/libs/$(TARGET_ARCH_ABI)/android_api.txt
+	@echo $(NDK_TOOLCHAIN) > $(LOCAL_PATH)/libs/$(TARGET_ARCH_ABI)/ndk_toolchain.txt
 	@test -f $(LOCAL_PATH)/obj/local/$(TARGET_ARCH_ABI)/libhfuzz.a && \
 	  cp $(LOCAL_PATH)/obj/local/$(TARGET_ARCH_ABI)/libhfuzz.a \
 	    $(LOCAL_PATH)/libs/$(TARGET_ARCH_ABI)/libhfuzz.a || true