diff --git a/tatt.5 b/tatt.5
index c40d34c..492b33b 100644
--- a/tatt.5
+++ b/tatt.5
@@ -77,6 +77,13 @@ which usually resides \fI /usr/lib/${python}/site-packages/tatt \fI
 .br
 #emergeopts="-v"
 
+.br
+# Whether to depclean package dependencies before each build test
+.br
+# (only applies to usecombis). Set any non-empty value to use.
+.br
+#cleandeps="yes"
+
 .br
 # Bugzilla API key, generated at \fIhttps://bugs.gentoo.org/userprefs.cgi?tab=apikey\fP
 .br
diff --git a/tatt/dot-tatt-spec b/tatt/dot-tatt-spec
index 33aff95..f4df4eb 100644
--- a/tatt/dot-tatt-spec
+++ b/tatt/dot-tatt-spec
@@ -5,6 +5,7 @@ unmaskdir=string(default="/etc/portage/package.accept_keywords")
 arch=string(default="x86")
 defaultopts=string(default="")
 emergeopts=string(default="")
+cleandeps=string(default="")
 rdeps=integer(0,512,default=10)
 usecombis=integer(0,512,default=12)
 repodir=string(default="")
diff --git a/tatt/scriptwriter.py b/tatt/scriptwriter.py
index c540626..fdc12e5 100644
--- a/tatt/scriptwriter.py
+++ b/tatt/scriptwriter.py
@@ -32,6 +32,7 @@ def scriptTemplate(job, config, filename):
 
     snippet = snippetfile.read()
     snippet = snippet.replace("@@EMERGEOPTS@@", config['emergeopts'])
+    snippet = snippet.replace("@@CLEANDEPS@@", config['cleandeps'])
     if job.bugnumber:
         snippet = snippet.replace("@@BUG@@", job.bugnumber)
     else:
diff --git a/templates/tatt_functions.sh b/templates/tatt_functions.sh
index 75f6ba4..884190b 100644
--- a/templates/tatt_functions.sh
+++ b/templates/tatt_functions.sh
@@ -44,6 +44,11 @@ function tatt_pkg_error
 
 function tatt_test_pkg
 {
+  # unmerge dependencies before tests
+  if [[ -n $TATT_CLEANDEPS ]]; then
+    CLEAN_DELAY=0 emerge -cq
+  fi
+
   if [ "${1:?}" == "--test" ]; then
     shift
     if ! emerge --onlydeps -1 --with-test-deps ${TATT_EMERGEOPTS} "${1:?}"; then
@@ -53,6 +58,11 @@ function tatt_test_pkg
     TFEATURES="${FEATURES} test"
   else
     TFEATURES="${FEATURES}"
+    # if not testing, install regular deps first
+    if ! emerge --onlydeps -1 ${TATT_EMERGEOPTS} "${1:?}"; then
+      echo "merging dependencies of $1 failed" >> "${TATT_REPORTFILE}"
+      return 0
+    fi
   fi
 
   # --usepkg-exclude needs the package name, so let's extract it
diff --git a/templates/use-header b/templates/use-header
index 9ae0cdb..1b925c5 100644
--- a/templates/use-header
+++ b/templates/use-header
@@ -7,6 +7,7 @@ export TATT_TEST_TYPE="use"
 export TATT_REPORTFILE="@@REPORTFILE@@"
 export TATT_BUILDLOGDIR="@@BUILDLOGDIR@@"
 export TATT_EMERGEOPTS="@@EMERGEOPTS@@"
+export TATT_CLEANDEPS="@@CLEANDEPS@@"
 
 source "@@TEMPLATEDIR@@tatt_functions.sh"