how to declare EU customs?

i'm sending an ex back his clothes to the Netherlands -- we were long distance and I'm from the UK royal mail is asking me to declare a customs value but I'm not sure how to fill out the values because they're all clothes he already had and they're not new.. what should I be putting so that he doesn't get charged any customs?

When you fill in the forms asking whether you are a business or an individual you will also be asked what you are sending. You cross the box “other” and then say returning personal belongings.
You then have to itemise what is in the box so you list each item, ( you might have to give a weight for each item) and then you just put a non zero value for each item. It doesn’t matter what you put as there isn’t any duty on this type of item, so I would try to approach a realistic second hand value, just in case the parcel goes missing, even if they’ll never pay you that unless you take out insurance. If none of the items are expensive brands just put a couple of £’s because no one will really pay any attention to it.

ahh you're an absolute star thank you so much! its like a hoodie jumper and some pyjammas so I'm thinking of listing them as like £10 each n pjs at like £3 but yeah! its also asked for a weight but I have no scales so I've just been estimating roughly... hopefully that's all good?

ahh you're an absolute star thank you so much! its like a hoodie jumper and some pyjammas so I'm thinking of listing them as like £10 each n pjs at like £3 but yeah! its also asked for a weight but I have no scales so I've just been estimating roughly... hopefully that's all good?

Given the cost and hassle of sending stuff internationally, unless these items have some kind of sentimental value to their owner, you could ask your ex (if you're still in contact) whether you could just donate them to charity/drop them in a clothes bank.