How to Sign Out and Clear Companion-App Information on Public Devices
The safest public-device login is the one you can avoid. Prefer your own phone, a temporary access link that does not expose the full account, or waiting until you control a device. If you must use a library computer, hotel terminal, workplace kiosk, or borrowed machine, use the browser's guest or private session rather than adding your browser profile. That reduces local history and cookies after all private windows close, but it does not make the device trustworthy: administrators, extensions, network controls, or unwanted recording software may still observe activity, and downloads remain as separate files. Keep the session short, do not open old private conversations, and do not approve a remembered login. On departure, follow an ordered chain: sign out of the companion app, sign out of the identity provider if it opened a separate session, close every guest window, remove files you created, clear granted site permissions, and verify or revoke the session from a trusted device.
Reduce the account surface before signing in
Confirm the exact official web address from a trusted source and type or open it yourself. Do not install the companion app, browser extension, remote-support tool, certificate, or unknown update on a public device. Choose Guest or a private window without adding your personal browser profile. Decline Save password, Keep me signed in, Sync, Remember this device, notification permission, camera and microphone unless the current task truly requires them. Use the account's normal multifactor method on a device you control; never copy backup codes into a public text file or leave a prompt approved for later. Open only the minimum page needed. A private window reduces ordinary local residue when closed, but cannot establish that the operating system or hardware is free from observation.
Sign out inside the companion app first
Use the app's Account, Settings, Profile, or Security menu and choose Sign out—do not simply close the tab. Wait until the app returns to a signed-out page, then test only by refreshing once; do not re-enter the password. If the app uses Google, Apple, Microsoft, or another identity provider, observe whether that provider is still signed in in a separate tab. Sign out of that session too if you created it for this visit, taking care not to alter another person's existing account. If the app provides “sign out all sessions,” do not use it casually on a shared workflow; reserve it for your own account when you intend to close every device. Record a case or confirmation only if necessary, without downloading private chat content.
Close the browsing container and handle files separately
Close every Guest or private window, not only the companion-app tab. Google states that guest browsing activity is removed from the computer when all Guest windows close, while downloaded files remain. Before closing, inspect the browser's download list for files you created during this session and delete only those exact files through the device's permitted interface; emptying a shared system trash or clearing all users' browser data may affect others and is not appropriate without ownership or policy authority. Remove any temporary print job you personally created if the kiosk exposes a user queue. Do not use aggressive cleanup utilities. If the device prevents file removal, note the filename and location and ask the authorized administrator to remove that specific item.
Review permissions, notifications, and adjacent services
If you granted microphone, camera, clipboard, downloads, pop-ups, or notifications to the companion-app site, use the browser's visible site controls to reset permissions for that site. Check whether an image was copied into a document, attached to webmail, opened in cloud drive, or placed in a print portal; each service may have its own session and recent-file list. Sign out from sessions you personally opened and remove only the items you created. Do not delete system logs, browser applications, or another user's files. Clear a shared clipboard only when the operating system provides an ordinary user control and doing so will not overwrite someone else's needed material; otherwise avoid placing sensitive text there in the first place. Close all remaining private windows afterward.
Use a trusted device to verify and revoke access
From your own phone or computer, open the companion app's security page and the identity provider's recent-activity or device list. Find the public session using time, browser, and approximate location, then revoke it if it remains active or you are uncertain. Apple documents reviewing the Apple Account device list and removing devices that should no longer have access; other providers have their own session pages. Check for a new remembered device, passkey, recovery method, app password, or forwarding rule you did not intentionally add. Changing the account password is appropriate when you entered it into a device you now believe was monitored, see unknown activity, or cannot revoke a session—not automatically after every properly closed guest login. If you change it, update only your trusted devices.
Run a short departure checklist and document exceptions
Before walking away, confirm: app signed out; identity provider signed out; all private or Guest windows closed; your downloads and print jobs handled; site permissions reset; public session absent or revoked from a trusted device. Also check that no phone number, email, username, or conversation remains visible in the browser's back screen. If the machine freezes or the kiosk prevents sign-out, stop trying to repair a device you do not own. Move to a trusted device, revoke sessions, review recent activity, and contact the venue administrator with the time and terminal number without disclosing chat content. For the future, carry a non-sensitive list of official URLs and know where the companion app's session-management page is. A repeatable exit is more reliable than trying to remember every possible trace under time pressure.
Common questions
Is private browsing enough on a public computer?
No. It can reduce ordinary cookies and history after every private window closes, but it does not control device administrators, monitoring software, extensions, networks, downloads, or files you created.
Should I clear the entire browser history before leaving?
Not on a device you do not own. Use Guest or private browsing, close all of its windows, and remove only files and permissions created by your session without affecting other users.
Must I change my password after every public-device login?
Not automatically. First revoke the session and review activity from a trusted device. Change it if exposure is plausible, activity is unknown, or access cannot be closed.