> ## Documentation Index
> Fetch the complete documentation index at: https://docs.abbyy.com/llms.txt
> Use this file to discover all available pages before exploring further.

# CleanCacheDictionary Method of the FRPage Object

This method deletes all words from the cache dictionary. The cache dictionary is a small dictionary (about a hundred words) which can be changed easily during processing. The cache dictionaries can be used when it is possible to select a dictionary more precisely, if you found new information about the document during processing.

<Warning>
  To use the cache dictionary, you should set the [IEngine::AutoCleanRecognizerSession](/fine-reader/engine/api-reference/engine-object-iengine-interface/properties#autocleanrecognizersession) property to FALSE. The AutoCleanRecognizerSession property is set to TRUE by default, which means that FineReader Engine cleans its recognition session after recognition of each page, in which case the cache dictionary is cleaned too. To prevent accidental destruction of user data, FineReader Engine prohibits using of cache dictionaries in this mode. If you use the cache dictionary, it is your concern to clean the recognition session manually by calling the [IEngine::CleanRecognizerSession](/fine-reader/engine/api-reference/engine-object-iengine-interface/supplementary-methods/cleanrecognizersession-method) method when necessary. See the description of the method to find out when it is necessary to clean the recognition session.
</Warning>

## Syntax

### C++

```cpp theme={null}
HRESULT CleanCacheDictionary( IRecognizerParams* params );
```

### C\#

```csharp theme={null}
void CleanCacheDictionary( IRecognizerParams params );
```

### Visual Basic .NET

```vb theme={null}
Sub CleanCacheDictionary(params As IRecognizerParams)
```

## Parameters

params

\[in] The [RecognizerParams](/fine-reader/engine/api-reference/parameter-objects/preprocessing-analysis-recognition-and-synthesis-parameters/recognizerparams) object that stores parameters of page processing.

## Return values

This method has no specific return values. It returns the [standard return values of ABBYY FineReader Engine functions](/fine-reader/engine/api-reference/return-codes).

## See also

[FRPage](/fine-reader/engine/api-reference/document-related-objects/frpage)

[AddWordToCacheDictionary](/fine-reader/engine/api-reference/document-related-objects/frpage/addwordtocachedictionary-method)

[AddWordsToCacheDictionary](/fine-reader/engine/api-reference/document-related-objects/frpage/addwordstocachedictionary-method)

[Working with Dictionaries](/fine-reader/engine/guided-tour/advanced-techniques/working-with-dictionaries)