I sell it as stock art.
I write tutorials
I design merchandise
I turn them into screen prints or art prints.
Edit your leftover designs into screen prints and art prints you can make at home and sell in an online shop like Etsy.
I built a giveaway pack for my website.
A lot of the time client work can end up being general stuff that anyone could get some use out of. Sets of icons, Photoshop brushes, themes and other items can make awesome giveaway packs to bring traffic to your monetized blog or portfolio website.
I use leftover card designs for my own promo material.
If you made a knock out business card or rack card design for a client, that you didn’t end up using, it can be a huge time saver next time you have a promotion you want to make some marketing materials for.
If nothing else, it can boost your portfolio. In either case, your business gets a promotional boost.
I tap into the power of affiliate programs.
Write a review or how-to of a product or service that was used in the making of the unused work and post it on a blog with an affiliate link.
More ways to turn unused designs into cash?
None of these on their own will make you rich overnight but if you use them as a whole package in addition to your normal client work they will add a nice bit of extra income without a lot of extra work.
What are some techniques you use to boost your passive income and reuse the leftover client work?
Let me know in the comments on this post.