What to Do With Nonvegan Items?
You are correct in thinking that wearing animal products, such as leather sandals, would appear hypocritical and could easily send a distorted message about veganism to others. To avoid wastefulness, some vegans wear their old nonvegan items only in the seclusion of their own home and put on their "veganwear" when they are out in public. This addresses the issue of frugality on two levels: utilizing what is already owned and extending the life of one's vegan products through prudent use. However, many vegans find wearing animal-based commodities to be ethically and emotionally excruciating and they cannot bear to don them even in private. Consequently, each vegan must determine her or his own threshold of tolerance and make choices based on individual need and economic circumstance.
There are many creative and practical ways to dispose of animal-based commodities such as yard sales, consignment shops, thrift stores, shelters, gifts to nonvegan friends or relatives, and so forth. Some vegans donate the proceeds from the sale of their nonvegan items to animal rights organizations; others use the profits to purchase vegan replacements.
Nonperishable foodstuffs can be donated to food banks, shelters, or public kitchens. Even if these organizations don't generally deal in vegetarian/vegan fare, they are usually very grateful for donations of any kind and will put them to good use.
If you feel you cannot part with your pre-vegan commodities right now, then hold onto them until you are prepared to let them go. When you are ready, you will be able to devise imaginative and serviceable ways to discard them. I think you'll find that releasing the final remnants of death from your home is an incredibly liberating experience -- one filled with unfettered joy and the satisfaction of no longer needing to justify apparent conflicts of conscience.