diff --git a/src/main/kotlin/com/cubetiqs/money/MoneyConfig.kt b/src/main/kotlin/com/cubetiqs/money/MoneyConfig.kt
index 9f3b433..16b7ada 100644
--- a/src/main/kotlin/com/cubetiqs/money/MoneyConfig.kt
+++ b/src/main/kotlin/com/cubetiqs/money/MoneyConfig.kt
@@ -26,7 +26,7 @@ object MoneyConfig {
      */
     private var properties: MoneyConfigProperties? = null
 
-    val propertiesBuilder = MoneyConfigProperties.MoneyConfigPropertiesBuilder()
+    private val propertiesBuilder = MoneyConfigProperties.MoneyConfigPropertiesBuilder()
 
     private fun getProperties(): MoneyConfigProperties {
         return properties ?: propertiesBuilder.build()
@@ -43,14 +43,16 @@ object MoneyConfig {
      * Value is money's value (Double)
      */
     fun parse(config: String, clearAllStates: Boolean = true) {
+        // remove all states, if needed
         if (clearAllStates) {
             MoneyConfig.config.clear()
         }
+
         val rates = config.split(getProperties().deliSplit)
         rates.map { i ->
             val temp = i.split(getProperties().deliEqual)
             if (temp.size == 2) {
-                val currency = temp[0].toUpperCase()
+                val currency = temp[0].toUpperCase().trim()
                 val value = temp[1].toDouble()
                 if (MoneyConfig.config.containsKey(currency)) {
                     MoneyConfig.config.replace(currency, value)
@@ -63,6 +65,15 @@ object MoneyConfig {
         }
     }
 
+    fun appendRate(currency: String, rate: Double) = apply {
+        val currencyKey = currency.toUpperCase().trim()
+        if (config.containsKey(currencyKey)) {
+            config.replace(currencyKey, rate)
+        } else {
+            config[currencyKey] = rate
+        }
+    }
+
     // all currencies with its rate
     fun getConfig() = config
 
@@ -97,4 +108,6 @@ object MoneyConfig {
             }
         }
     }
+
+    fun builder() = MoneyConfigProperties.MoneyConfigPropertiesBuilder()
 }
\ No newline at end of file
diff --git a/src/main/kotlin/com/cubetiqs/money/MoneyExtension.kt b/src/main/kotlin/com/cubetiqs/money/MoneyExtension.kt
index 2afabf3..baa1fbb 100644
--- a/src/main/kotlin/com/cubetiqs/money/MoneyExtension.kt
+++ b/src/main/kotlin/com/cubetiqs/money/MoneyExtension.kt
@@ -4,4 +4,19 @@ fun StdMoney.exchangeTo(currency: StdMoney.Currency): StdMoney {
     return MoneyExchangeUtils.exchange(this, currency)
 }
 
-fun StdMoney.isMatchedCurrency(currency: StdMoney.Currency) = this.getMoneyCurrency().getCurrency().equals(currency.getCurrency(), ignoreCase = true)
\ No newline at end of file
+fun StdMoney.isMatchedCurrency(currency: StdMoney.Currency) =
+    this.getMoneyCurrency().getCurrency().equals(currency.getCurrency(), ignoreCase = true)
+
+inline fun buildMoneyConfigProperties(
+    builderAction: MoneyConfig.MoneyConfigProperties.MoneyConfigPropertiesBuilder.() -> Unit
+): MoneyConfig.MoneyConfigProperties {
+    return MoneyConfig
+        .builder().apply(builderAction)
+        .build()
+}
+
+inline fun applyMoneyConfig(
+    builderAction: MoneyConfig.() -> Unit,
+) {
+    MoneyConfig.apply(builderAction)
+}
\ No newline at end of file
diff --git a/src/main/kotlin/com/cubetiqs/money/SpecialString.kt b/src/main/kotlin/com/cubetiqs/money/SpecialString.kt
deleted file mode 100644
index 0637f57..0000000
--- a/src/main/kotlin/com/cubetiqs/money/SpecialString.kt
+++ /dev/null
@@ -1,5 +0,0 @@
-package com.cubetiqs.money
-
-@Target(AnnotationTarget.FIELD)
-@Retention(AnnotationRetention.RUNTIME)
-annotation class SpecialString(val value: String = "", val upperCase: Boolean = true, val trim: Boolean = true)
\ No newline at end of file
diff --git a/src/main/kotlin/com/cubetiqs/money/SpecialStringProcessor.kt b/src/main/kotlin/com/cubetiqs/money/SpecialStringProcessor.kt
deleted file mode 100644
index 71e7cf9..0000000
--- a/src/main/kotlin/com/cubetiqs/money/SpecialStringProcessor.kt
+++ /dev/null
@@ -1,37 +0,0 @@
-package com.cubetiqs.money
-
-import java.lang.reflect.Field
-
-class SpecialStringProcessor: ISerializer {
-    override fun <T> serialize(data: T?): T? {
-        if (data == null) return null
-        val clazz = data.javaClass
-        clazz.declaredFields.forEach {
-            it.isAccessible = true
-            if (it.isAnnotationPresent(SpecialString::class.java) && it.genericType == String::class.java) {
-                val annotationValues = it.getAnnotation(SpecialString::class.java)
-                var value = it.get(data).toString()
-                if (annotationValues.trim) {
-                    value = value.trim()
-                }
-                if (annotationValues.upperCase) {
-                    value = value.toUpperCase()
-                }
-                it.set(data, value)
-            }
-        }
-
-        return data
-    }
-
-    private fun getSerializeKey(field: Field): String {
-        val annotationValue = field.getAnnotation(SpecialString::class.java).value
-        return if (annotationValue.isEmpty()) {
-            field.name
-        } else annotationValue
-    }
-}
-
-interface ISerializer {
-    fun <T> serialize(data: T?): T?
-}
\ No newline at end of file
diff --git a/src/test/kotlin/MoneyTests.kt b/src/test/kotlin/MoneyTests.kt
index 353e46c..7e2854b 100644
--- a/src/test/kotlin/MoneyTests.kt
+++ b/src/test/kotlin/MoneyTests.kt
@@ -1,23 +1,28 @@
-import com.cubetiqs.money.Money
-import com.cubetiqs.money.MoneyConfig
-import com.cubetiqs.money.MoneyCurrency
-import com.cubetiqs.money.MoneyExchangeUtils
+import com.cubetiqs.money.*
 import org.junit.Assert
 import org.junit.Test
 
 class MoneyTests {
     @Test
     fun exchange_2usd_to_khr_test() {
-        val properties = MoneyConfig
-            .MoneyConfigProperties
-            .MoneyConfigPropertiesBuilder()
-            .setDeliEqual(':')
-            .setDeliSplit(',')
-            .build()
+//        val properties = MoneyConfig
+//            .MoneyConfigProperties
+//            .MoneyConfigPropertiesBuilder()
+//            .setDeliEqual(':')
+//            .setDeliSplit(',')
+//            .build()
 
-        MoneyConfig
-            .setProperties(properties)
-            .parse("USD:1,KHR:4000")
+        val properties = buildMoneyConfigProperties {
+            setDeliEqual(':')
+            setDeliSplit(',')
+        }
+
+        applyMoneyConfig {
+            setProperties(properties)
+            // parse("USD:1,KHR:4000")
+            appendRate("usd", 1.0)
+            appendRate("khr", 4000.0)
+        }
 
         // Is valid for money config?
         Assert.assertTrue(MoneyConfig.isValid())