Apollo filters get you close, but an export still needs a pass before it goes into your sending tool. Filters run on database fields, and those fields can be out of date. Here's a cleanup routine for any Apollo (or similar database) CSV.
Name, title, company, company website, email, industry, employee count, country and LinkedIn URL. Hide the rest while you work. ListGrader recognises common header names like First Name, Title, Company, Website, Email, Industry, # Employees and Country.
If you've exported several searches, merge them and remove duplicate emails before anything else. Also check the new list against people you've already emailed.
Database records can outlive the company. A dead or parked domain is a clear signal to cut the row. A redirect to a different domain often means a rebrand or an acquisition.
Drop malformed addresses. Separate role inboxes (info@, sales@) and free-provider addresses into their own segment. Then run an email verifier before you send at volume.
Search filters are broad. Re-check that the title is a real buyer, the employee count is in your range, the industry is right (read the homepage if unsure) and the country is one you serve.
Grade every row Gold, Silver, Bronze or Cut (see the free template). Import only Gold, and Silver once fixed, into Instantly or Smartlead, with the tier as a custom field so you can personalise by tier. More detail: how to clean a lead list and qualifying bought lists.
Drop your Apollo CSV into ListGrader, describe your ICP, and get every row tiered with a reason, website and email flags, and an Instantly/Smartlead-ready export.