diff --git a/build.gradle.kts b/build.gradle.kts
index 9d9996c..ec62673 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -286,9 +286,8 @@ val compressJar = tasks.register<ProcessJar>("compressJar") {
 	archiveVersion = "modVersion"()
 	archiveClassifier = ""
 
-	addFileProcessor(setOf("json", "mcmeta"), Compressors.json)
-
-	addFileProcessor(setOf("jar"), Compressors.storeJars)
+	addFileProcessor(extensions = setOf("json", "mcmeta"), processor = Compressors.json)
+	addFileProcessor(extensions = setOf("jar"), processor = Compressors.storeJars)
 
 	addDirProcessor { dir -> // proguard
 		val temp = temporaryDir.resolve("proguard")
diff --git a/buildSrc/src/main/kotlin/Compressors.kt b/buildSrc/src/main/kotlin/Compressors.kt
index 477c08e..7c18d34 100644
--- a/buildSrc/src/main/kotlin/Compressors.kt
+++ b/buildSrc/src/main/kotlin/Compressors.kt
@@ -7,11 +7,13 @@ import java.util.jar.JarOutputStream
 import java.util.zip.Deflater
 
 object Compressors {
-	val json = { input: File ->
-		input.outputStream().write(JsonOutput.toJson(JsonSlurper().parse(input)).toByteArray())
+	// minify json
+	val json: FileProcessor = {
+		it.outputStream().write(JsonOutput.toJson(JsonSlurper().parse(it)).toByteArray())
 	}
 
-	val storeJars = { input: File ->
+	// store JIJs instead of deflating them so that the outer jar compresses the entire thing (most of the time better)
+	val storeJars: FileProcessor = { input ->
 		val tmp = input.copyTo(File.createTempFile(input.nameWithoutExtension, ".jar"), overwrite = true)
 		JarInputStream(tmp.inputStream()).use { ins ->
 			JarOutputStream(input.outputStream()).use { out ->
diff --git a/buildSrc/src/main/kotlin/ProcessJar.kt b/buildSrc/src/main/kotlin/ProcessJar.kt
index 4411ab9..feffed1 100644
--- a/buildSrc/src/main/kotlin/ProcessJar.kt
+++ b/buildSrc/src/main/kotlin/ProcessJar.kt
@@ -1,3 +1,5 @@
+import org.gradle.api.file.RegularFileProperty
+import org.gradle.api.provider.ListProperty
 import org.gradle.api.tasks.InputFile
 import org.gradle.jvm.tasks.Jar
 import java.io.File
@@ -7,34 +9,40 @@ import java.util.zip.Deflater
 
 typealias FileProcessor = (File) -> Unit
 
-open class ProcessJar : Jar() {
-	val input = project.objects.fileProperty()
+abstract class ProcessJar : Jar() {
+	abstract val input: RegularFileProperty
 		@InputFile get
 
-	private val processors = mutableListOf<FileProcessor>()
+	abstract val processors: ListProperty<FileProcessor>
 
 	init {
 		group = "build"
 		outputs.upToDateWhen { false }
+
+		addFileProcessor(paths = setOf("META-INF/MANIFEST.MF")) { file ->
+			manifest.from(file)
+			file.delete()
+			file.createNewFile()
+			manifest.effectiveManifest.writeTo(file)
+		}
 	}
 
 	fun addFileProcessor(regex: Regex, processor: FileProcessor) {
 		processors.add {
 			it.walkTopDown().forEach { file ->
-				if (file.extension.matches(regex))
+				if (file.path.matches(regex))
 					processor(file)
 			}
 		}
 	}
 
-	fun addFileProcessor(vararg extensions: String, processor: FileProcessor) {
-		addFileProcessor(extensions.asIterable(), processor)
-	}
-
-	fun addFileProcessor(extensions: Iterable<String>, processor: FileProcessor) {
+	fun addFileProcessor(extensions: Iterable<String> = emptySet(),
+						 names: Iterable<String> = emptySet(),
+						 paths: Iterable<String> = emptySet(),
+						 processor: FileProcessor) {
 		processors.add {
 			it.walkTopDown().forEach { file ->
-				if (file.extension in extensions)
+				if (file.extension in extensions || file.name in names || file.path in paths)
 					processor(file)
 			}
 		}
@@ -62,16 +70,8 @@ open class ProcessJar : Jar() {
 			into(dir)
 		}
 
-		processors.forEach { it(dir) }
-
-		// merge manifests
-		val manifestFile = dir.resolve("META-INF/MANIFEST.MF")
-		if (manifestFile.exists()) {
-			manifest.from(manifestFile)
-			manifestFile.delete()
-			manifestFile.createNewFile()
-			manifest.effectiveManifest.writeTo(manifestFile)
-		}
+		processors.finalizeValue()
+		processors.get().forEach { it(dir) }
 
 		// repack jar
 		JarOutputStream(archiveFile.get().asFile.outputStream()).use { jos ->