People sure like to talk about decluttering, and I agree that being mindful about your possessions and their relevance to your life can be very beneficial, but the same process of decluttering and cleaning applies to our minds too.
We keep a lot of rubbish in there, after all. Too often we let it pile up and make our heads full of obstacles. So how can we clear out our minds? Well, it all depends on us as individuals. Some of us will carefully pick up something from the top of a pile and start to think about it, and some of us will upturn the pile entirely and destroy the base, flinging specks of debris in all directions. Some of us do a combination of both, or go for a different approach. It's usually an accident too, but we can be purposeful, and we should be.
One thing that inhibits this process, I think, is having this clear path of what we supposedly ought to do or be. It can help to put your sense of morality or responsibility to one side when trying to organise your head. Retroactive moralising and pre-emptive worrying might be helpful and necessary sometimes, but for the most part it's best to push yourself towards focusing your consciousness on right now.
The past and the future aren't you. The present is as you as you will ever be.
Just don't forget, spring cleaning should extent to your mind, so get the duster out.