Best way to fix brassy blonde hair at home?

Brass in blonde happens because those warmer undertones naturally develop as your color oxidizes over time, especially with sun exposure and heat styling. Purple shampoo alone won't fix it once you're that far gone - it's more of a maintenance thing for fresh highlights. At this point you've got two real options: an at-home toner or a salon visit.

If you want to DIY it, grab a demi-permanent or semi-permanent toner in an ash or platinum shade from a beauty supply store. The key is going lighter on the developer (10 or 20 volume, not 40) and leaving it on for less time than the box says, like start checking at 15 minutes instead of 25. Honestly this is where people mess up - they're impatient and leave it on too long and end up with greenish or ashy hair that looks weird. You could also try a gloss-type product made specifically for brass if you want something gentler. Just do a strand test first because you don't know exactly what's happening underneath.

That said, if you're already nervous about it or your hair's been through a lot, the salon route isn't the worst call. They can actually see what they're working with and won't over-process. It'll cost you more but you won't risk messing it up further. If you do go the home toner route and it doesn't work out, you can always go to a salon after to fix it - just maybe space it out a week or two so you're not hammering your hair with back-to-back processing.

At this point you're probably looking at actual toner rather than just purple shampoo - store-bought toners can work but they're hit or miss depending on how deep the brass is, and if you mess up the mixing or timing you could end up with ashy or patchy results. honestly a salon visit is worth it if your highlights are this far gone, since a professional can assess exactly what level you're at and apply the right toner properly rather than gambling on a box.