diff --git a/src/persistence/memory.rs b/src/persistence/memory.rs
index 1b95ebed..5afa9287 100644
--- a/src/persistence/memory.rs
+++ b/src/persistence/memory.rs
@@ -73,10 +73,10 @@ use crate::LIB_NAME_RGB_STORAGE;
 //////////
 
 /// Hoard is an in-memory stash useful for WASM implementations.
-#[derive(Getters, Clone, Debug, Default)]
+#[derive(Getters, Clone, Debug)]
 #[getter(prefix = "debug_")]
-#[derive(StrictType, StrictEncode, StrictDecode)]
-#[strict_type(lib = LIB_NAME_RGB_STORAGE)]
+#[derive(StrictType, StrictDumb, StrictEncode, StrictDecode)]
+#[strict_type(lib = LIB_NAME_RGB_STORAGE, dumb = Self::in_memory())]
 pub struct MemStash {
     #[strict_type(skip)]
     dirty: bool,
@@ -102,6 +102,28 @@ pub struct MemStash {
 impl StrictSerialize for MemStash {}
 impl StrictDeserialize for MemStash {}
 
+impl MemStash {
+    pub fn in_memory() -> Self {
+        Self {
+            dirty: false,
+            filename: None,
+            schemata: empty!(),
+            ifaces: empty!(),
+            geneses: empty!(),
+            suppl: empty!(),
+            bundles: empty!(),
+            extensions: empty!(),
+            witnesses: empty!(),
+            attachments: empty!(),
+            secret_seals: empty!(),
+            type_system: none!(),
+            identities: empty!(),
+            libs: empty!(),
+            sigs: empty!(),
+        }
+    }
+}
+
 impl StoreTransaction for MemStash {
     type TransactionErr = SerializeError;
 
@@ -434,10 +456,10 @@ impl StashWriteProvider for MemStash {
 // STATE
 //////////
 
-#[derive(Getters, Clone, Debug, Default)]
+#[derive(Getters, Clone, Debug)]
 #[getter(prefix = "debug_")]
-#[derive(StrictType, StrictEncode, StrictDecode)]
-#[strict_type(lib = LIB_NAME_RGB_STORAGE)]
+#[derive(StrictType, StrictDumb, StrictEncode, StrictDecode)]
+#[strict_type(lib = LIB_NAME_RGB_STORAGE, dumb = Self::in_memory())]
 pub struct MemState {
     #[strict_type(skip)]
     dirty: bool,
@@ -452,6 +474,17 @@ pub struct MemState {
 impl StrictSerialize for MemState {}
 impl StrictDeserialize for MemState {}
 
+impl MemState {
+    pub fn in_memory() -> Self {
+        Self {
+            dirty: false,
+            filename: None,
+            witnesses: empty!(),
+            contracts: empty!(),
+        }
+    }
+}
+
 impl StoreTransaction for MemState {
     type TransactionErr = SerializeError;
 
@@ -1132,10 +1165,10 @@ pub struct ContractIndex {
     outpoint_opouts: MediumOrdMap<XOutputSeal, MediumOrdSet<Opout>>,
 }
 
-#[derive(Getters, Clone, Debug, Default)]
+#[derive(Getters, Clone, Debug)]
 #[getter(prefix = "debug_")]
-#[derive(StrictType, StrictEncode, StrictDecode)]
-#[strict_type(lib = LIB_NAME_RGB_STORAGE)]
+#[derive(StrictType, StrictDumb, StrictEncode, StrictDecode)]
+#[strict_type(lib = LIB_NAME_RGB_STORAGE, dumb = Self::in_memory())]
 pub struct MemIndex {
     #[strict_type(skip)]
     dirty: bool,
@@ -1153,6 +1186,20 @@ pub struct MemIndex {
 impl StrictSerialize for MemIndex {}
 impl StrictDeserialize for MemIndex {}
 
+impl MemIndex {
+    pub fn in_memory() -> Self {
+        Self {
+            dirty: false,
+            filename: None,
+            op_bundle_index: empty!(),
+            bundle_contract_index: empty!(),
+            bundle_witness_index: empty!(),
+            contract_index: empty!(),
+            terminal_index: empty!(),
+        }
+    }
+}
+
 impl StoreTransaction for MemIndex {
     type TransactionErr = SerializeError;
 
@@ -1421,7 +1468,7 @@ mod fs {
             Self {
                 dirty: true,
                 filename: Some(filename.to_owned()),
-                ..default!()
+                ..Self::in_memory()
             }
         }
 
@@ -1458,7 +1505,7 @@ mod fs {
             Self {
                 dirty: true,
                 filename: Some(filename.to_owned()),
-                ..default!()
+                ..Self::in_memory()
             }
         }
 
@@ -1495,7 +1542,7 @@ mod fs {
             Self {
                 dirty: true,
                 filename: Some(filename.to_owned()),
-                ..default!()
+                ..Self::in_memory()
             }
         }
 
diff --git a/src/persistence/stock.rs b/src/persistence/stock.rs
index d4723855..008c99d5 100644
--- a/src/persistence/stock.rs
+++ b/src/persistence/stock.rs
@@ -368,7 +368,10 @@ where
 }
 
 impl Stock {
-    pub fn in_memory() -> Self { Self::default() }
+    #[inline]
+    pub fn in_memory() -> Self {
+        Self::with(MemStash::in_memory(), MemState::in_memory(), MemIndex::in_memory())
+    }
 }
 
 #[cfg(feature = "fs")]
@@ -1306,16 +1309,14 @@ mod test {
 
     #[test]
     fn test_consign() {
-        let mut stock = Stock::<MemStash, MemState, MemIndex>::default();
+        let mut stock = Stock::in_memory();
         let seal = XChain::with(
             rgbcore::Layer1::Bitcoin,
             GraphSeal::new_random_vout(bp::dbc::Method::OpretFirst, Vout::from_u32(0)),
         );
         let secret_seal = seal.conceal();
 
-        stock
-            .store_secret_seal(seal)
-            .expect_err("we can't store to FS and fail here since we have not filename assigned");
+        stock.store_secret_seal(seal).unwrap();
         let contract_id =
             ContractId::from_baid64_str("rgb:qFuT6DN8-9AuO95M-7R8R8Mc-AZvs7zG-obum1Va-BRnweKk")
                 .unwrap();
@@ -1326,7 +1327,7 @@ mod test {
 
     #[test]
     fn test_export_contract() {
-        let stock = Stock::<MemStash, MemState, MemIndex>::default();
+        let stock = Stock::in_memory();
         let contract_id =
             ContractId::from_baid64_str("rgb:qFuT6DN8-9AuO95M-7R8R8Mc-AZvs7zG-obum1Va-BRnweKk")
                 .unwrap();
@@ -1337,7 +1338,7 @@ mod test {
 
     #[test]
     fn test_export_schema() {
-        let stock = Stock::<MemStash, MemState, MemIndex>::default();
+        let stock = Stock::in_memory();
         let hasher = Sha256::default();
         let schema_id = SchemaId::from(hasher);
         if let Ok(schema) = stock.export_schema(schema_id) {
@@ -1347,7 +1348,7 @@ mod test {
 
     #[test]
     fn test_blank_builder_ifaceid() {
-        let stock = Stock::<MemStash, MemState, MemIndex>::default();
+        let stock = Stock::in_memory();
         let hasher = Sha256::default();
         let iface_id = IfaceId::from(hasher.clone());
         let bytes_hash = hasher.finish();
@@ -1359,7 +1360,7 @@ mod test {
 
     #[test]
     fn test_blank_builder_ifacename() {
-        let stock = Stock::<MemStash, MemState, MemIndex>::default();
+        let stock = Stock::in_memory();
         let hasher = Sha256::default();
         let bytes_hash = hasher.finish();
         let contract_id = ContractId::copy_from_slice(bytes_hash).unwrap();
@@ -1372,7 +1373,7 @@ mod test {
 
     #[test]
     fn test_transition_builder() {
-        let stock = Stock::<MemStash, MemState, MemIndex>::default();
+        let stock = Stock::in_memory();
         let hasher = Sha256::default();
         let iface_id = IfaceId::from(hasher.clone());