There is also a HE detergent that comes as a powder, but your issue is really how to use up your "life time supply" of conventional detergent. I do not think that there is really any clothing you cannot wash in a conventional top load machine as long as you use the correct settings.

It is true that HE machines require HE detergent. Conventional detergent willover suds and make a total mess and could wreck the machine