Get rid of Whatsapp junk photos, videos and documents

Most of people face a problem that when they buy a new phone they use it well but with time the storage gets full and the phone becomes slow. We can't install any app and constantly get notification to clear storage.

For the photos or videos we take on our camera we can upload them on Google photos. But there are something which still eats up our space. 

Whatsapp Recycle Bin

I checked this thing in my phone and also on many people's phone that most of the space are aquired by the photos and videos which we get on whatsapp, we keep them thinking that we'll need these photos or videos in near future. So, we don't delete them and after few days neither those things are useful for us nor we put that effort to find them and delete them.

I couldn't find any automatic way to get rid of this problem, but what I have done is created a group in my whatsapp which has no participant other than I and named that group as "Recycle Bin". I turned on disapearing message on that group and set the time to 90 days. 

Whenever I get any photo or video from anyone which I think that it can be required in near future but after a few days there will be no use of it, I send them to that group and delete from the original sender's chat. If I need that photo in future I search it from that Recycle Bin folder and after 90 days it deletes the files automatically, so we get rid of those junk medias from our phones.

If anyone has any other solution for this problem. Please suggest. 

The solution given by @dexter_greycells is so useful. check that from his comment below..