diff --git a/search/src/main/scala/weco/api/search/services/ImagesRequestBuilder.scala b/search/src/main/scala/weco/api/search/services/ImagesRequestBuilder.scala
index 996ccc94d..a5c76ddc7 100644
--- a/search/src/main/scala/weco/api/search/services/ImagesRequestBuilder.scala
+++ b/search/src/main/scala/weco/api/search/services/ImagesRequestBuilder.scala
@@ -53,10 +53,10 @@ class ImagesRequestBuilder()
             searchOptions.searchQuery.isDefined || searchOptions.color.isDefined,
           includes = Seq("display", "vectorValues.reducedFeatures"),
           aggs = filteredAggregationBuilder(pairables).filteredAggregations,
-          preFilter = unpairables.map(buildImageFilterQuery),
+          preFilter = unpairables.collect(buildImageFilterQuery),
           postFilter = Some(
             must(
-              searchOptions.filters.map(buildImageFilterQuery)
+              searchOptions.filters.collect(buildImageFilterQuery)
             )
           ),
           knn = searchOptions.color.map(ColorQuery(_))
@@ -111,8 +111,7 @@ class ImagesRequestBuilder()
         searchOptions.sortOrder
     }
 
-  private def buildImageFilterQuery(filter: ImageFilter): Query =
-    filter match {
+  private val buildImageFilterQuery: PartialFunction[ImageFilter, Query] =  {
       case LicenseFilter(licenseIds) =>
         termsQuery(
           field = "filterableValues.locations.license.id",
@@ -134,10 +133,10 @@ class ImagesRequestBuilder()
           genreLabels
         )
       case GenreConceptFilter(conceptIds) if conceptIds.nonEmpty =>
-          termsQuery(
-            "filterableValues.source.genres.concepts.id",
-            conceptIds
-          )
+        termsQuery(
+          "filterableValues.source.genres.concepts.id",
+          conceptIds
+        )
       case SubjectLabelFilter(subjectLabels) =>
         termsQuery(
           "filterableValues.source.subjects.label",
diff --git a/search/src/main/scala/weco/api/search/services/WorksRequestBuilder.scala b/search/src/main/scala/weco/api/search/services/WorksRequestBuilder.scala
index 27db572f6..fd98a3205 100644
--- a/search/src/main/scala/weco/api/search/services/WorksRequestBuilder.scala
+++ b/search/src/main/scala/weco/api/search/services/WorksRequestBuilder.scala
@@ -50,10 +50,10 @@ object WorksRequestBuilder
           sortByScore = searchOptions.searchQuery.isDefined,
           includes = Seq("display", "type"),
           aggs = filteredAggregationBuilder(pairables).filteredAggregations,
-          preFilter = (VisibleWorkFilter :: unpairables).map(buildWorkFilterQuery),
+          preFilter = (VisibleWorkFilter :: unpairables).collect(buildWorkFilterQuery),
           postFilter = Some(
             must(
-              pairables.map(buildWorkFilterQuery)
+              pairables.collect(buildWorkFilterQuery)
             )
           )
         )
@@ -139,8 +139,7 @@ object WorksRequestBuilder
         searchOptions.sortOrder
     }
 
-  private def buildWorkFilterQuery(workFilter: WorkFilter): Query =
-    workFilter match {
+  val buildWorkFilterQuery: PartialFunction[WorkFilter, Query] = {
       case VisibleWorkFilter =>
         termQuery(field = "type", value = "Visible")
       case FormatFilter(formatIds) =>