"Do you want to keep this book?" asks professional declutterer Beverly Wade. "Yes or no?" How can you be so ruthless? "I'm not ruthless," she says. "Just speedy." It's Hölderlin's selected poetry. What kind of barbarian would I be without it? "Fine," she says putting it on the "yes" pile.

We're in my study, trying to organise my books. There are horizontal piles on vertical rows, proof copies stuffed under the desk. "What about this?" Beverly says, holding Sartre's Being And Nothingness. I've had it on my shelves for 15 years without reading it. I should keep it. "Should?" says Beverly, an eyebrow rising. She starts a pile of "maybes".

I have two problems, Beverly tells me: guilt and inertia. Inertia explains the something that's festering behind the books. There's a funny story about those mousetraps, I say. Beverly, sensibly, doesn't pause to hear it. The guilt takes two forms. Intellectual guilt – I should have read Schrödinger's Cat and Kant's Critique Of Pure Reason and, until I have, I'm stuck with the buggers. And relationship guilt – I can't give up on books people have given me. Beverly offers a liberating piece of advice: "A gift becomes yours to do with what you want," she says.

And then there are the books signed by people I've interviewed and books that, for sentimental reasons, I'll never let go. "Sentiment is a very good reason for keeping a book – because it's important to you," she says.

Her top tip? Take stock. Imagine your books are T-shirts. Realise you have 25 black T-shirts before buying another. Then work out which are worth keeping. "Making a hierarchy is useful to help you declutter. A shelf of unread books is also helpful." We arrange a half-shelf of books I haven't read culled from the "maybe" pile.

But those books are on borrowed time. That way I can overcome the guilt and inertia. Beverly tells me she once typed a list of her books. Three years later she checked which she'd read and got rid of those she hadn't. "Can you warrant having something in your life unloved and unwanted?" she asks. Above the unread books she's created a shelf of volumes I'm using as research for a book I'm writing. It's now organised rather than a teetering pile. For the shame pile under the desk, she counsels putting proof books in a bag and, after a month, taking them to a charity shop unless I've used them. Again, the time limit is key in the war against festering.

• Beverly Wade, cluttergone.co.uk/Beverly.html