When browsing through home improvement tips, you’re bound to come across some popular tips that will actually cost you more money in the long run. You’ll find some of these pieces of advice shared all around the internet, but just because they look popular doesn’t mean they are helpful. If you’re like most people, you want home improvement ideas and DIY tips worth your while. You want to minimize wastage and save money.

Following the wrong kind of DIY advice will do you more harm than good. Here’s a list of popular DIY tips for improving your home that will prove costly in the long run, and should therefore be treated as nothing more than myths:

Use lemons to clean garbage disposals

Go by this piece of advice if you want your plumber to pay you a visit soon. This DIY fix is somewhat popular, but you need to tread carefully here. An expert plumber will tell you that while citric acid does a good job as a natural deodorizer, it won’t take long before metal in the disposal starts to corrode. The lemon peel is also likely to clog the pipes and cause damage to the grinding components. This means having to buy a new disposal and hiring a plumber to fix it.

There’s a better way to clean your garbage disposal that doesn’t involve lemons. Just turn the disposal on, run cold water, and throw in at least two trays of ice cubes while the water is running. The water and ice cubes will clean up any buildup on the disposal’s walls and grinders. To deodorize, use vinegar. You can find some more excellent DIY advice like this on DIY Luke.

Change HVAC air filter every month

The typical advice you’ll see ever so often is that HVAC filters should be changed every month. While it’s true that changing air filters on a regular basis is recommended if you want to keep the HVAC unit running efficiently, you don’t have to do it every month. Many homeowners throw away perfectly fine filters, not knowing that the filters could work for at least another month or two. That means incurring an extra cost of about $100 per year.

The Department of Energy has a better suggestion: be sure to check the air filter every month, but not necessarily change it. You may change it if it doesn’t look clean, but make sure to do a replacement once every three months.

Seal ductwork with duct tape

Just because it’s called duct tape doesn’t mean it’s the right material for sealing leaks in the HVAC system. The US Department of Energy did run some tests and established that the duct tape will take just a few years to deteriorate. This is because the HVAC unit discharges hot air, which slowly degrades the glue and allows the conditioned air to leak without having done its job. In the end, you’ll be faced with higher energy bills before you know where the problem lies.

A better solution for sealing the ductwork is duct mastic. This is a soft and sticky substance similar to caulk that will dry up fast when applied. For wider gaps, use duct mastic in combination with fiberglass mesh. Be sure to use gloves when working on metal ducts, as the edges can be very sharp, and also because mastic can get really messy.

Use bleach to get rid of mold

While bleach can be effective at removing mold on non-porous surfaces, it’s not as effective on porous or absorbent surfaces. Unfortunately, mold likes to show up in the more porous areas, such as drywall, caulk, insulation, grout and carpet. So what the bleach does on such surfaces is feed further growth of mold, as the mold will just absorb the water from the bleach. Also keep in mind that bleach is a health hazard that is best avoided whenever possible.

An anti-fungal product that removes the mold right at its root would be the safer and cheaper solution. If the mold covers too much space (more than ten square feet), calling a mold removal specialist is advised. If you decide to do it yourself, be sure to wear protective gear—think tough gloves and a respirator.