diff --git a/app/models/ip_pool_rule.rb b/app/models/ip_pool_rule.rb
index 5fc20a2..8a85a6b 100644
--- a/app/models/ip_pool_rule.rb
+++ b/app/models/ip_pool_rule.rb
@@ -68,18 +68,22 @@ class IPPoolRule < ApplicationRecord
     errors.add :ip_pool_id, "must belong to the organization"
   end
 
-  def self.address_matches?(condition, address)
-    address = Postal::Helpers.strip_name_from_address(address)
-    if condition =~ /@/
-      parts = address.split("@")
-      domain = parts.pop
-      uname = parts.join("@")
-      uname, = uname.split("+", 2)
-      condition == "#{uname}@#{domain}"
-    else
-      # Match as a domain
-      condition == address.split("@").last
+  class << self
+
+    def address_matches?(condition, address)
+      address = Postal::Helpers.strip_name_from_address(address)
+      if condition =~ /@/
+        parts = address.split("@")
+        domain = parts.pop
+        uname = parts.join("@")
+        uname, = uname.split("+", 2)
+        condition == "#{uname}@#{domain}"
+      else
+        # Match as a domain
+        condition == address.split("@").last
+      end
     end
+
   end
 
 end
diff --git a/app/models/route.rb b/app/models/route.rb
index 9d59f5c..3ef415c 100644
--- a/app/models/route.rb
+++ b/app/models/route.rb
@@ -219,12 +219,16 @@ class Route < ApplicationRecord
     errors.add :base, "Additional routes are not permitted unless the primary route is an actual endpoint"
   end
 
-  def self.find_by_name_and_domain(name, domain)
-    route = Route.includes(:domain).where(name: name, domains: { name: domain }).first
-    if route.nil?
-      route = Route.includes(:domain).where(name: "*", domains: { name: domain }).first
+  class << self
+
+    def find_by_name_and_domain(name, domain)
+      route = Route.includes(:domain).where(name: name, domains: { name: domain }).first
+      if route.nil?
+        route = Route.includes(:domain).where(name: "*", domains: { name: domain }).first
+      end
+      route
     end
-    route
+
   end
 
 end
diff --git a/lib/postal/smtp_sender.rb b/lib/postal/smtp_sender.rb
index dff04f4..3dfdf2f 100644
--- a/lib/postal/smtp_sender.rb
+++ b/lib/postal/smtp_sender.rb
@@ -252,39 +252,43 @@ module Postal
       records.first&.address&.to_s&.downcase
     end
 
-    def self.ssl_context_with_verify
-      @ssl_context_with_verify ||= begin
-        c = OpenSSL::SSL::SSLContext.new
-        c.verify_mode = OpenSSL::SSL::VERIFY_PEER
-        c.cert_store = OpenSSL::X509::Store.new
-        c.cert_store.set_default_paths
-        c
+    class << self
+
+      def ssl_context_with_verify
+        @ssl_context_with_verify ||= begin
+          c = OpenSSL::SSL::SSLContext.new
+          c.verify_mode = OpenSSL::SSL::VERIFY_PEER
+          c.cert_store = OpenSSL::X509::Store.new
+          c.cert_store.set_default_paths
+          c
+        end
       end
-    end
 
-    def self.ssl_context_without_verify
-      @ssl_context_without_verify ||= begin
-        c = OpenSSL::SSL::SSLContext.new
-        c.verify_mode = OpenSSL::SSL::VERIFY_NONE
-        c
+      def ssl_context_without_verify
+        @ssl_context_without_verify ||= begin
+          c = OpenSSL::SSL::SSLContext.new
+          c.verify_mode = OpenSSL::SSL::VERIFY_NONE
+          c
+        end
       end
-    end
 
-    def self.default_helo_hostname
-      Postal.config.dns.helo_hostname || Postal.config.dns.smtp_server_hostname || "localhost"
-    end
+      def default_helo_hostname
+        Postal.config.dns.helo_hostname || Postal.config.dns.smtp_server_hostname || "localhost"
+      end
 
-    def self.relay_hosts
-      hosts = Postal.config.smtp_relays.map do |relay|
-        next unless relay.hostname.present?
+      def relay_hosts
+        hosts = Postal.config.smtp_relays.map do |relay|
+          next unless relay.hostname.present?
+
+          {
+            hostname: relay.hostname,
+            port: relay.port,
+            ssl_mode: relay.ssl_mode
+          }
+        end.compact
+        hosts.empty? ? nil : hosts
+      end
 
-        {
-          hostname: relay.hostname,
-          port: relay.port,
-          ssl_mode: relay.ssl_mode
-        }
-      end.compact
-      hosts.empty? ? nil : hosts
     end
 
   end
diff --git a/lib/postal/worker.rb b/lib/postal/worker.rb
index 2d425a2..c9ef066 100644
--- a/lib/postal/worker.rb
+++ b/lib/postal/worker.rb
@@ -195,21 +195,25 @@ module Postal
       self.class.logger
     end
 
-    def self.logger
-      Postal.logger_for(:worker)
-    end
+    class << self
 
-    def self.job_channel
-      @channel ||= Postal::RabbitMQ.create_channel
-    end
+      def logger
+        Postal.logger_for(:worker)
+      end
 
-    def self.job_queue(name)
-      @job_queues ||= {}
-      @job_queues[name] ||= job_channel.queue("deliver-jobs-#{name}", durable: true, arguments: { "x-message-ttl" => 60_000 })
-    end
+      def job_channel
+        @channel ||= Postal::RabbitMQ.create_channel
+      end
+
+      def job_queue(name)
+        @job_queues ||= {}
+        @job_queues[name] ||= job_channel.queue("deliver-jobs-#{name}", durable: true, arguments: { "x-message-ttl" => 60_000 })
+      end
+
+      def local_ip?(ip)
+        !!(ip =~ /\A(127\.|fe80:|::)/)
+      end
 
-    def self.local_ip?(ip)
-      !!(ip =~ /\A(127\.|fe80:|::)/)
     end
 
   end