In some cases you could experiment the AMP validation failing because of the usage of invalid tags that are not compliant with the Google AMP format or you may have to hide, exclude or remove undesired elements from an AMP page.
For this reason JAmp has a special parameter that allows to exclude invalid or unwanted tags. To do this you must use the parameter named 'Elements to remove by CSS selectors' and specify a value that matches tags that you want to remove, for example to exclude all elements having a CSS class 'noamp' you can enter: *.noamp
Keep in mind that if you have certain placeholder code that is not replaced by plugins on AMP pages and it's not included in any specific HTML tag, to remove it you may need to wrap it within a tag that can be referenced through the parameter above, for example:
<div class="noamp">...plugin code...</div>.