diff --git a/contracts/src/ERC20FixedDenomination.sol b/contracts/src/ERC20FixedDenomination.sol
index 059e8eb..68b395c 100644
--- a/contracts/src/ERC20FixedDenomination.sol
+++ b/contracts/src/ERC20FixedDenomination.sol
@@ -154,7 +154,6 @@ contract ERC20FixedDenomination is ERC404NullOwnerCappedUpgradeable {
     /// @notice Returns metadata URI for NFT tokens
     /// @dev Returns a data URI with JSON metadata fetched from the main Ethscriptions contract
     function tokenURI(uint256 mintId) public view virtual override returns (string memory) {
-        _validateTokenId(mintId);
         ownerOf(mintId); // reverts on invalid / nonexistent
 
         // Get the ethscriptionId for this mintId from the manager
diff --git a/contracts/src/ERC20NullOwnerCappedUpgradeable.sol b/contracts/src/ERC20NullOwnerCappedUpgradeable.sol
deleted file mode 100644
index 91b7cda..0000000
--- a/contracts/src/ERC20NullOwnerCappedUpgradeable.sol
+++ /dev/null
@@ -1,189 +0,0 @@
-// SPDX-License-Identifier: MIT
-pragma solidity 0.8.24;
-
-import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
-import {IERC20Metadata} from "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
-import {ContextUpgradeable} from "@openzeppelin/contracts-upgradeable/utils/ContextUpgradeable.sol";
-import {IERC20Errors} from "@openzeppelin/contracts/interfaces/draft-IERC6093.sol";
-import {Initializable} from "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";
-
-/// @title ERC20NullOwnerCappedUpgradeable
-/// @notice ERC20 (Upgradeable) + Cap adapted to treat address(0) as a valid holder; single storage struct
-abstract contract ERC20NullOwnerCappedUpgradeable is Initializable, ContextUpgradeable, IERC20, IERC20Metadata, IERC20Errors {
-    /// @custom:storage-location erc7201:ethscriptions.storage.ERC20NullOwnerCapped
-    struct TokenStorage {
-        mapping(address account => uint256) balances;
-        mapping(address account => mapping(address spender => uint256)) allowances;
-        uint256 totalSupply;
-        string name;
-        string symbol;
-        uint256 cap;
-    }
-
-    // Unique storage slot for this combined ERC20 + Cap storage
-    // keccak256(abi.encode(uint256(keccak256("ethscriptions.storage.ERC20NullOwnerCapped")) - 1)) & ~bytes32(uint256(0xff))
-    bytes32 private constant STORAGE_LOCATION = 0x4d6f413771b260e6694ffc0cfc1fc0bdb079c880580315446b9e26b778417b00;
-
-    function _getS() private pure returns (TokenStorage storage $) {
-        assembly {
-            $.slot := STORAGE_LOCATION
-        }
-    }
-
-    // Errors copied from OZ
-    error ERC20ExceededCap(uint256 increasedSupply, uint256 cap);
-    error ERC20InvalidCap(uint256 cap);
-
-    // Initializers
-    function __ERC20_init(string memory name_, string memory symbol_) internal onlyInitializing {
-        __ERC20_init_unchained(name_, symbol_);
-    }
-
-    function __ERC20_init_unchained(string memory name_, string memory symbol_) internal onlyInitializing {
-        TokenStorage storage $ = _getS();
-        $.name = name_;
-        $.symbol = symbol_;
-    }
-
-    function __ERC20Capped_init(uint256 cap_) internal onlyInitializing {
-        __ERC20Capped_init_unchained(cap_);
-    }
-
-    function __ERC20Capped_init_unchained(uint256 cap_) internal onlyInitializing {
-        TokenStorage storage $ = _getS();
-        if (cap_ == 0) {
-            revert ERC20InvalidCap(0);
-        }
-        $.cap = cap_;
-    }
-
-    // Views
-    function name() public view virtual returns (string memory) {
-        TokenStorage storage $ = _getS();
-        return $.name;
-    }
-
-    function symbol() public view virtual returns (string memory) {
-        TokenStorage storage $ = _getS();
-        return $.symbol;
-    }
-
-    function decimals() public view virtual returns (uint8) {
-        return 18;
-    }
-
-    function totalSupply() public view virtual returns (uint256) {
-        TokenStorage storage $ = _getS();
-        return $.totalSupply;
-    }
-
-    function balanceOf(address account) public view virtual returns (uint256) {
-        TokenStorage storage $ = _getS();
-        return $.balances[account];
-    }
-
-    function allowance(address owner, address spender) public view virtual returns (uint256) {
-        TokenStorage storage $ = _getS();
-        return $.allowances[owner][spender];
-    }
-
-    // External ERC-20 (can be overridden to restrict usage in child)
-    function transfer(address to, uint256 value) public virtual returns (bool) {
-        address owner = _msgSender();
-        _transfer(owner, to, value);
-        return true;
-    }
-
-    function approve(address spender, uint256 value) public virtual returns (bool) {
-        address owner = _msgSender();
-        _approve(owner, spender, value);
-        return true;
-    }
-
-    function transferFrom(address from, address to, uint256 value) public virtual returns (bool) {
-        address spender = _msgSender();
-        _spendAllowance(from, spender, value);
-        _transfer(from, to, value);
-        return true;
-    }
-
-    // Internal core
-    function _transfer(address from, address to, uint256 value) internal {
-        if (from == address(0)) {
-            revert ERC20InvalidSender(address(0));
-        }
-        // Allow `to == address(0)` to support null-owner semantics
-        _update(from, to, value);
-    }
-
-    // Update balances without affecting total supply (supports from/to == address(0))
-    function _update(address from, address to, uint256 value) internal virtual {
-        TokenStorage storage $ = _getS();
-        // Debit from
-        uint256 fromBalance = $.balances[from];
-        if (fromBalance < value) {
-            revert ERC20InsufficientBalance(from, fromBalance, value);
-        }
-        unchecked {
-            $.balances[from] = fromBalance - value;
-        }
-        // Credit to
-        unchecked {
-            $.balances[to] += value;
-        }
-        emit Transfer(from, to, value);
-    }
-
-    // Mint (null-owner aware): increases totalSupply and credits recipient (can be address(0))
-    function _mint(address account, uint256 value) internal {
-        TokenStorage storage $ = _getS();
-        
-        uint256 newSupply = $.totalSupply + value;
-        if (newSupply > $.cap) {
-            revert ERC20ExceededCap(newSupply, $.cap);
-        }
-        
-        $.totalSupply = newSupply;
-        
-        unchecked { $.balances[account] += value; }
-        
-        emit Transfer(address(0), account, value);
-    }
-
-    // Approvals
-    function _approve(address owner, address spender, uint256 value) internal {
-        _approve(owner, spender, value, true);
-    }
-
-    function _approve(address owner, address spender, uint256 value, bool emitEvent) internal virtual {
-        TokenStorage storage $ = _getS();
-        if (owner == address(0)) {
-            revert ERC20InvalidApprover(address(0));
-        }
-        if (spender == address(0)) {
-            revert ERC20InvalidSpender(address(0));
-        }
-        $.allowances[owner][spender] = value;
-        if (emitEvent) {
-            emit Approval(owner, spender, value);
-        }
-    }
-
-    function _spendAllowance(address owner, address spender, uint256 value) internal virtual {
-        uint256 currentAllowance = allowance(owner, spender);
-        if (currentAllowance < type(uint256).max) {
-            if (currentAllowance < value) {
-                revert ERC20InsufficientAllowance(spender, currentAllowance, value);
-            }
-            unchecked {
-                _approve(owner, spender, currentAllowance - value, false);
-            }
-        }
-    }
-
-    // Cap view
-    function maxSupply() public view virtual returns (uint256) {
-        TokenStorage storage $ = _getS();
-        return $.cap;
-    }
-}