For peanut butter, I use a small screw-top container. I think it's made by Nalgene and holds 1 or 2 fl oz. I don't always want the amount that a single serving gives me, so this works well. Easy to clean and reload. And, regardless of what king of peanut butter I use at home, I always carry a commercial brand like JIF on the trail. It has enough chemicals in it so that it doesn't separate and I don't care about the added sugar when hiking.
For mayo, soy sauce, honey, etc., I just use the small packets.
Btw, these guys are great for refillable tubes and such. Cheap and durable and amazingly fast delivery. I use their "rum runner" flasks for carrying extra water. 32oz containers are less than $5 and weigh 0.8oz. I've never had one leak. http://www.easytravelerinc.com/