Add note about how to clear package cache

doc/user/packages/maven_repository/index.md

@@ -813,6 +813,19 @@ You can play around with the regex and try your version strings on [this regular
 
 ## Troubleshooting
 
+To improve performance, Maven caches files related to a package. If you encounter issues, clear
+the cache with these commands:
+
+```shell
+rm -rf ~/.m2/repository
+```
+
+If you're using Gradle, run this command to clear the cache:
+
+```shell
+rm -rf ~/.gradle/caches
+```
+
 ### Review network trace logs
 
 If you are having issues with the Maven Repository, you may want to review network trace logs.

doc/user/packages/npm_registry/index.md

@@ -455,6 +455,14 @@ Due to a bug in npm 6.9.0, deleting distribution tags fails. Make sure your npm
 When troubleshooting npm issues, first run the same command with the `--verbose` flag to confirm
 what registry you are hitting.
 
+To improve performance, npm caches files related to a package. Note that npm doesn't remove data by
+itself. The cache grows as new packages are installed. If you encounter issues, clear the cache with
+this command:
+
+```shell
+npm cache clean --force
+```
+
 ### Error running Yarn with the Package Registry for npm registry
 
 If you are using [Yarn](https://classic.yarnpkg.com/en/) with the npm registry, you may get

doc/user/packages/nuget_repository/index.md

@@ -422,3 +422,12 @@ CLI (`dotnet`):
 - `dotnet nuget push`: Upload a package to the registry.
 - `nuget install`: Install a package from the registry.
 - `dotnet add`: Install a package from the registry.
+
+## Troubleshooting
+
+To improve performance, NuGet caches files related to a package. If you encounter issues, clear the
+cache with this command:
+
+```shell
+nuget locals all -clear
+```